No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
The effects of isometric exercise training on resting blood pressure and orthostatic tolerance in humans
Experimental Physiology
Abstract
Isometric exercise training has been shown to reduce resting blood pressure, but the effect that this might have on orthostatic tolerance is poorly understood. Changes in orthostatic tolerance may also be dependent on whether the upper or lower limbs of the body are trained using isometric exercise. Twenty-seven subjects were allocated to either a training or control group. A training group first undertook 5 weeks of isometric exercise training of the legs, and after an 8 week intervening period, a second training group containing six subjects from the initial training group, undertook 5 weeks of isometric arm-training. The control group were asked to continue their normal daily activities throughout the 18 weeks of the study. In all subjects orthostatic tolerance, assessed using lower body negative pressure (LBNP), and resting blood pressure were measured before and after each of the 5 week training or control periods. Estimated lean leg volume was determined before and after leg-training. During all LBNP tests, heart rate and blood pressure were recorded each minute, and the time taken to reach the highest heart rate was derived (time to peak HR). Resting systolic blood pressure (mean +/- S.D.), when measured during the last week of training, was significantly reduced after both leg (-10 +/- 8.7 mmHg) and arm (-12.4 +/- 9.3 mmHg; P < 0.05) isometric exercise training, compared to controls. This reduction disappeared when blood pressure was measured immediately before the LBNP tests, which followed training. Orthostatic tolerance only increased after leg-training (20.8 +/- 16.4 LTI; P < 0.05) and was accompanied by an increased time to peak HR (119.8 +/- 106.3 beats min(-1); P < 0.05) in this group. Blood pressure responses to LBNP did not change after arm-training, leg-training or in controls (P > 0.05). There was a small but significant increase in estimated lean leg volume after leg-training (0.1 +/- 0.1 1; P < 0.05). These results suggest that lower resting blood pressure is probably not responsible for the increased orthostatic tolerance after isometric exercise training of the legs. Rather, it is possible that the training altered some other aspect of cardiovascular control during orthostatic stress that was apparent in the changes in heart rate. Leg-training was accompanied by increases in estimated lean leg volume. The effects of isometric training on orthostatic tolerance appear to be specific to limbs that are directly involved in LBNP testing.
... Isometric exercise training (IET) lowers RBP in prehypertensive and normotensive individuals at various ages (see (13,14) for review and meta-analysis, respectively). Several studies have assessed the effects of bilateral leg IET in young, normotensive subjects (15)(16)(17)(18). Moreover, significant reductions in SBP, DBP, and mean arterial pressure (MAP) have been seen in less than 5 weeks of training at 20%-30% maximum voluntary contraction (MVC) (15,17), demonstrating the efficacy of IET over short training periods in young subjects. ...
... Several studies have assessed the effects of bilateral leg IET in young, normotensive subjects (15)(16)(17)(18). Moreover, significant reductions in SBP, DBP, and mean arterial pressure (MAP) have been seen in less than 5 weeks of training at 20%-30% maximum voluntary contraction (MVC) (15,17), demonstrating the efficacy of IET over short training periods in young subjects. However, there is a paucity of data regarding the effect of extended IET programs on the elderly and very limited information about the effects of detraining on RBP. ...
... Therefore, this is the first study to incorporate a relatively long IET program, followed by a long post-IET monitoring period. It has been reported that short-term RBP adaptations that are quickly lost after training cessation (15,17,19) may be more due to a physiological change than anatomical (27). Our detraining data, along with previous reports (15,17,19), suggest that the mechanisms responsible for RBP reductions induced by handgrip IET are phasic, like adaptations associated with traditional forms of resistance exercise training (33)(34)(35). ...
Background
Elderly people are particularly affected by rising systolic blood pressure (SBP). We hypothesized that resting blood pressure (RBP)-reducing isometric exercise training (IET) can be delivered in a group setting with older adults.
Methods
Participants (63–88 years; N = 19) completed IET at 30% maximum voluntary contraction, 3 days a week for 12 weeks. RBP was measured weekly throughout, plus 6 weeks posttraining. Control participants did not engage in IET (N = 5). Changes in RBP were assessed using a 2-way repeated-measures analysis of variance.
Results
IET induced significant reductions in SBP (−10.5 mmHg; P < 0.05), but SBP also declined unexpectedly in the control group (−4.5 mmHg; P < 0.05). Diastolic blood pressure declined in the IET group only (−4.7 mmHg; P < 0.05). There were no significant differences between groups for SBP or diastolic blood pressure (P > 0.05). At 6 weeks posttraining, SBP was still 9.4 mmHg below baseline in the IET group only. A unique finding was that the clinically significant RBP reductions persisted for 6 weeks after IET.
Conclusions
Handgrip IET may be an effective antihypertensive intervention, which persists for several weeks in older adults, even when training ceases.
... Reports suggest that reductions in BP following aerobic and resistance training can return to pre-training levels within as little as 2 weeks following a detraining period (Meredith et al., 1990;Murray et al., 2006;Moker et al., 2014). Although previous studies have evaluated the effects of detraining following aerobic and resistance (Elliott et al., 2002;Fatouros et al., 2006;Moker et al., 2014) exercise periods, few studies (Wiley et al., 1992;Howden et al., 2002) have reported the effects of detraining following IRT in young healthy individuals. Since interruptions in training or prescribed exercise programmes are likely to occur it is important to quantify changes in ambulatory BP resulting from the cessation of exercise. ...
... To the authors' knowledge, there is little published research that quantifies the changes in BP that occur as a result of the cessation of an IRT programme in young healthy adults, particularly 24-h ambulatory BP. Both Wiley et al. (1992) and Howden et al. (2002) suggest resting BP returns to pre-training levels following a period (5-8 weeks) of detraining. Therefore, it is important to not only establish the time scale of the BP reductions but to also know how rapidly they regress following the cessation of the training. ...
... However, other studies have reported a regression to, or close to, baseline values following various lengths of detraining preceded by a period of resistance training (Moker et al., 2014) or a combination of resistance and aerobic training (Volaklis et al., 2006;Moker et al., 2014). In addition, Howden et al. (2002) reported no difference from baseline resting SBP measures to those taken after 5 weeks of isometric leg training followed by an 8-week washout period (in preparation for another isometric training period), in effect a detraining period. However, the study's focus was not to investigate the effects of the detraining period and therefore the effects of the washout period were not fully reported. ...
Isometric resistance training (IRT) has been shown to reduce resting and ambulatory blood pressure (BP), as well as BP variability and morning BP surge (MBPS). However, there are no data available regarding how long after cessation of IRT these effects are maintained. Therefore, the purpose of this study was to determine the effects of 8 weeks of detraining on resting BP, ambulatory BP and MBPS following 8 weeks of IRT in a population of young normotensive individuals and to further substantiate previously reported reductions in MBPS following IRT. Twenty-five apparently healthy participants with resting BP within the normal range (16 men, age = 23 ± 6 years; 9 women, age = 22 ± 4 years, resting BP: 123 ± 5/69 ± 7 mmHg) were randomly assigned to a training-detraining (TRA-DT, n = 13) or control (CON, n = 12) group. Resting BP, ambulatory BP and MBPS were measured prior to, after 8 weeks of bilateral leg IRT using an isokinetic dynamometer (4 × 2-min contractions at 20% MVC with 2-min rest periods, 3 days/week) and following an 8-week detraining period. There were significant reductions in 24-h ambulatory systolic BP (SBP) and calculated SBP average real variability (ARV) following IRT that were maintained after detraining (pre-to-post detraining, −6 ± 4 mmHg, p = 0.008, −2 ± 1.5 mmHg, p = 0.001). Similarly, the training-induced decreases in daytime SBP and daytime SBP ARV (pre-to-post detraining, −5 ± 6 mmHg, p = 0.001; −2 ± 1.2 mmHg, p = 0.001, respectively), MBPS (pre-to-post detraining, −6 ± 9 mmHg, p = 0.046) and resting SBP (pre-to-post detraining, −4 ± 6 mmHg, p = 0.044) were preserved. There were no changes in night-time or night-time SBP ARV across all time points (pre-to-post detraining, −1 ± 8 mmHg, p = 1.00, −0.7 ± 2.9 mmHg, p = 1.00). These results confirm that IRT causes significant reductions in resting BP, ambulatory BP, ambulatory ARV and MBPS. Importantly, the changes remained significantly lower than baseline for 8 weeks after cessation of training, suggesting a sustained effect of IRT.
... Forty-seven studies reported the chronic changes in resting blood pressure after isometric handgrip training (Ahmed et al., 2019;Allen et al., 2003;Alomari et al., 2010;Baddeley-White et al., 2019;Badrov, Bartol, et al., 2013;Badrov, Horton, et al., 2013Bank et al., 1998;Baross et al., 2017;Cahu Rodrigues et al., 2020;Carlson et al., 2016;Correia et al., 2020;Dempster et al., 2018;Dobrosielski et al., 2009;Farah et al., 2018;Gandhi, 2016;Garg et al., 2014;Goessler et al., 2018;Herrod et al., 2019;Hess et al., 2016;Howden et al., 2002;Lara et al., 2015;McGowan et al., 2006;McGowan, Visocchi, et al., 2007;Millar et al., 2007Millar et al., , 2008Millar et al., , 2013Mortimer & McKune, 2011;Ogbutor et al., 2019;Okamoto et al., 2020;Pagonas et al., 2017;Peters et al., 2006, Punia & Kulandaivelan, 2020Ray & Carrasco, 2000;Saito et al., 2009;Sinoway et al., 1996;Somani et al., 2017Somani et al., , 2018Somers et al., 1992;Souza et al., 2020;Stiller-Moldovan et al., 2012;Taylor et al., 2003;Wiley et al., 1992;Yamagata & Sako, 2020;Zhang, 2003) (Table 2). Graded press: noxious press stimuli are gradually increased at a certain rate (i.e., 0.5 kg per second) until participants indicate the feeling of pain. ...
... In total, 22 studies included a nonexercise control group, three studies included a sham-control group, one study provided a lifestyle modification program to both treatment and control groups, and 21 studies only had one or multiple isometric handgrip training groups. There were studies comparing the changes in resting blood pressure between sexes (Badrov et al., 2016;Somani et al., 2017), between Stage 1 hypertensives and Stage 2 hypertensives (Souza et al., 2020), between different exercise intensities (Hess et al., 2016), between bilateral and unilateral isometric handgrip training, (McGowan, Visocchi, et al., 2007;Millar et al., 2007), between isometric handgrip and knee extension training (Howden et al., 2002;Somani et al., 2018), between isometric handgrip and aerobic training Goessler et al., 2018) ...
... The reduction in resting blood pressures following isometric handgrip training is supported by a number of randomized controlled trials ( Howden et al., 2002;Wiley et al., 1992) and patients with peripheral artery disease . However, a nonrandomized clinical trial found that isometric handgrip training did not change mean arterial pressure in male patients with New York Heart Association Classes II and III heart failure compared to baseline values (Bank et al., 1998). ...
Isometric handgrip exercise has been suggested to promote some health‐related factors (e.g., lowering blood pressure). However, there is a need to evaluate whether this type of exercise can be included as an option to elicit these health‐related outcomes. The purpose of the article was to systematically review the acute and chronic effects of isometric handgrip exercise on resting blood pressure, pain sensation, cognitive function and blood lipids and lipoproteins. A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. A total of 89 studies met our inclusion criteria. Most randomized controlled trials (17/26) reported reductions in resting blood pressure (mostly systolic blood pressure) following isometric handgrip training. There were inconsistent results in isometric handgrip exercise‐induced hypotension (i.e., acute response). There was convincing evidence observed in randomized controlled trials (4/6) for isometric handgrip exercise‐induced hypoalgesia. Some randomized controlled trials (2/2) supported an improvement in memory performance, but not interference control (0/2), after a session of isometric handgrip exercise. None of the included studies found any effects of isometric handgrip training on blood lipids and lipoproteins. Isometric handgrip exercise appears to be an effective method to improve certain health‐related factors. The acute reductions in pain and blood pressure may share a similar central mechanism. However, training‐induced reductions in resting blood pressure may be driven by changes in the periphery. Additional work is needed to better understand if (and to what extent) isometric handgrip exercise (or training) influences cognitive function and blood lipids and lipoproteins.
... Six studies were included in the qualitative and quantitative analysis, with a total of 8 intervention groups and 139 normotensive adult participants (intervention group, n = 81; control group, n = 58). 1,5,6,8,17,24 Particularly, 2 intervention groups were excluded due to reported ranges for prehypertension mean SBP at baseline (high-intensity intervention group: mean ± SD SBP, 121.5 ± 4.6 mm Hg 24 ; knee extension intervention group: mean ± SD SBP, 121 ± 9.6 mm Hg 8 ). On the other hand, 5 studies used a parallel design 1,6,8,17,24 while the remainder used a crossover design. ...
... 1,5,6,8,17,24 Particularly, 2 intervention groups were excluded due to reported ranges for prehypertension mean SBP at baseline (high-intensity intervention group: mean ± SD SBP, 121.5 ± 4.6 mm Hg 24 ; knee extension intervention group: mean ± SD SBP, 121 ± 9.6 mm Hg 8 ). On the other hand, 5 studies used a parallel design 1,6,8,17,24 while the remainder used a crossover design. 5 Three of the 6 studies included participants of both sexes, 6,8,17 2 included only men, 5,24 and 1 article reported the inclusion of only women. 1 In general, studies reported how they measured BP. ...
... Five studies reported that they measured BP using automated brachial oscillometry. 1,5,8,17,24 One study measured BP using an automated sphygmomanometer 6 ( Table 1). ...
Context
Cardiovascular diseases cause 17 million deaths annually worldwide, of which hypertension is responsible for 9.4 million and a 7% burden of disease. High blood pressure is responsible for 45% of deaths from heart disease and 51% of deaths from stroke.
Objective
The aim of this systematic review and meta-analysis was to quantify the effect of isometric resistance training on systolic, diastolic, and mean arterial blood pressure (SBP, DBP, and MAP, respectively) values in normotensive adult participants.
Data Sources
This study was registered with the PROSPERO database. Eligible studies were identified after performing a systematic search within the following databases: PubMed, Scielo, BioMed Central, Clinical Trials, EMBASE, Cochrane Central Register of Controlled Trials, and EBSCO.
Study Selection
Randomized controlled trials that categorized participants as normotensive according to the guidelines of the American Heart Association and the American College of Cardiology were included.
Study Design
Systematic review with meta-analysis.
Level of Evidence
Level 1.
Data Extraction
Data related to participant characteristics, exercise programs, level of evidence, risk of bias, Consensus on Exercise Reporting Template, and outcomes of interest were systematically reviewed independently by 2 authors.
Results
A total of 6 randomized controlled trials were included. The following reductions in blood pressure (compared with the control group) were generated by isometric resistance training: SBP (mean difference [MD], −2.83 mm Hg; 95% CI, −3.95 to −1.72; P < 0.00001), DBP (MD, −2.73; 95% CI, −4.23 to −1.24; P = 0.0003), and MAP (MD, −3.07; 95% CI, −5.24 to −0.90; P = 0.005).
Conclusion
It appears that isometric resistance training reduces SBP, DBP, and MAP in normotensive young adults in a statistically significant and clinically relevant manner. This type of exercise could be considered effective in preventing arterial hypertension.
... Over several years, numerous studies have investigated the role of isometric resistance exercise training in reducing blood pressure (Wiley et al., 1992, Ray and Carrasco, 2000, Howden et al., 2002, Taylor et al., 2003, Peters et al., 2006, Millar et al., 2008. In fact, a current meta-analysis study reported that the reduction in resting blood pressure had been largest after isometric resistance exercise training (systolic: −10.9 mmHg, diastolic: −6.2 mmHg) compared to endurance (systolic: −3.5 mmHg, diastolic: −3.7 mmHg) and dynamic resistance exercise training (systolic: −1.8 mmHg, diastolic: −2.5 mmHg) (Cornelissen and Smart, 2013). ...
... Although the optimal protocol of the isometric resistance exercise training has not been established at present, the most common protocol of this exercise training is composed of four sets of 2 minutes' handgrip , Millar et al., 2008 or leg contractions (Howden et al., 2002) at 30 to 50 % of maximal voluntary contraction (MVC) (Wiley et al., 1992, Ray andCarrasco, 2000) with 1 to 4 minutes of rest period between each contraction (Wiley et al., 1992 that are conducted three to five times per week for 4 to 10 weeks (Devereux et al., 2010, Badrov et al., 2013. Relative to exercise trained-muscle, hand grip isometric exercise training (Wiley et al., 1992, Badrov et al., 2013 has been found to reduce resting blood pressure more than leg isometric exercise training (Baross et al., 2012). ...
... −3.5 mmHg, diastolic: −3.7 mmHg) and dynamic resistance exercise training (systolic: −1.8 mmHg, diastolic: −2.5mmHg). Moreover, several earlier studies suggested that the isometric exercise training protocol consisting of four sets of 2-minute handgrip , Millar et al., 2008 or leg contractions (Howden et al., 2002) at 30 % to 50 % of maximal voluntary contraction (MVC) (Wiley et al., 1992, Ray andCarrasco, 2000) with 1 to 4 minutes of rest period between each contraction (Wiley et al., 1992 conducted three to five times per week for 4 to 10 weeks (Devereux et al., 2010, Badrov et al., 2013 to be more effective in lowering resting blood pressure than endurance and dynamic resistance exercise training. ...
A disparity population data set in the current literature with limited reports
among Asian samples, coupled with the inconsistent findings among different ethnic
groups, and lack of information for the involvement of angiotensin I-converting
enzyme (ACE) I/D and alpha-actinin-3 (ACTN3) R/X gene polymorphisms in training
adaptation have limited the ability of researchers to draw meaningful conclusions
pertaining to the effects of these polymorphisms on human physical performance and
health. Therefore, this doctoral research implemented three series of studies to
examine the effects of ACE I/D and ACTN3 R/X gene polymorphisms on human
physical performance and health within the Malaysian population. In the first study,
DNA samples were retrieved via buccal cell from 180 Asians from Malaysia (70
males, 110 females) aged 20.4 ± 1.6 years, and 180 Caucasians from Australia (62
males, 118 females) aged 23.3 ± 3.6 years. In the second study, DNA samples were
retrieved from 180 well-trained Malaysian athletes (148 males, 32 females) aged
20.5 ± 1.9 years, 180 Malaysian sedentary controls, and 33 intermittent Australian
athletes (all males) aged 20.7 ± 4.0 years. Endurance and muscular performances of
Malaysian athletes were evaluated with 20 meters Yo-Yo intermittent recovery level
2 and maximal voluntary contraction tests, respectively. In the third study, thirty
normotensive, untrained males (ACE genotype: II = 10, ID = 10, and DD = 10),
xxi
undergone isometric handgrip training (four sets of 2 minutes isometric contractions
at 30% of maximal voluntary contraction, with 1 minute resting interval) 3 days per
week for 8 weeks. The result from the first study indicated that the distribution of
ACE I/D gene polymorphism varied among different ethnic groups, but not to
ACTN3 R/X gene polymorphism. The findings obtained from the second study
demonstrated that: a) The effects of these polymorphisms on endurance and
strength/power performances did not vary by ethnicity, b) The ACE D allele and
ACTN3 R allele conferred an advantage in activities that require strength/power, and
c) The ACE I allele and ACTN3 X allele did not influence endurance performance.
Finding from the final study demonstrated that ACE I/D gene polymorphism had a
positive influence in cardiovascular and muscular adaptations following isometric
handgrip training among normotensive men. Overall, this research reaffirms the
notion that strength/power performance is influenced by the ACE D allele and
ACTN3 R allele. In addition, this research concludes that the ACE I/D gene
polymorphism modulates response to isometric handgrip training in normotensive
men.
... Part of the problem has been a lack of uniformity regarding methods used to determine IET intensity. Previous studies have used a wide range of IET intensities based on a participant's maximum voluntary contraction (MVC) force (20-50%) to set IET intensity (Baross, Wiles, & Swaine, 2012;Devereux, Coleman, Wiles, & Swaine, 2012;Howden, Lightfoot, Brown, & Swaine, 2002;Millar et al., 2007Millar et al., , 2008Taylor et al., 2003;Wiley et al., 1992). However, training protocols, rest periods between each contraction and muscle groups trained were not consistent among these studies. ...
... Devereux, Wiles, and Swaine (2011) predicted an exercise intensity of 105.4% of an individual's 2-min torque peak (~30%EMG peak ) would elicit a 5-mmHg reduction in systolic blood pressure after 4 weeks of double-leg IET. Interestingly, a significant reduction in systolic blood pressure has been reported after only 3 weeks of bilateral quadriceps IET at 20%MVC (Howden et al., 2002). Taken together, this suggests a relationship between IET intensity and time to a reduction in resting blood pressure that is not fully understood. ...
... Several studies have used IET to induce reductions in resting blood pressure in both healthy participants and medication hypertensive patients (Howden et al., 2002;McGowan, Levy, McCartney, & MacDonald, 2007;Millar et al., 2007;Stiller-Moldovan, Kenno, & McGowan, 2012;Taylor et al., 2003;Wiley et al., 1992). Recent meta-analyses of IET studies reported average reductions in resting blood pressure that were substantial [−6.77 to −10.9 mmHg systolic blood pressure and −3.9 to −6.7 mmHg diastolic blood pressure (Carlson, Dieberg, Hess, Millar, & Smart, 2014;Cornelissen, Verheyden, Aubert, & Fagard, 2010;Owen, Wiles, & Swaine, 2010)] and similar to blood pressure reductions expected with pharmacological intervention. ...
Abstract To reduce resting blood pressure, a minimum isometric exercise training (IET) intensity has been suggested, but this is not known for short-term IET programmes. We therefore compared the effects of moderate- and low-intensity IET programmes on resting blood pressure. Forty normotensive participants (22.3 ± 3.4 years; 69.5 ± 15.5 kg; 170.2 ± 8.7 cm) were randomly assigned to groups of differing training intensities [20%EMGpeak (~23%MVC, maximum voluntary contraction, or 30%EMGpeak (~34%MVC)] or control group; 3 weeks of IET at 30%EMGpeak resulted in significant reductions in resting mean arterial pressure (e.g. -3.9 ± 1.0 mmHg, P < 0.001), whereas 20%EMGpeak did not (-2.3 ± 2.9 mmHg; P > 0.05). Moreover, after pooling all female versus male participants, IET induced a 6.9-mmHg reduction in systolic blood pressure in female participants, but only a 1.5-mmHg reduction in systolic blood pressure in male participants, although the difference was not significant. An IET intensity between 20%EMGpeak and 30%EMGpeak is sufficient to elicit significant resting blood pressure reductions in a short-term training period (3 weeks). In addition, sexual dimorphism may exist in the magnitude of reductions, but further work is required to confirm this possibility, which could be important in understanding the mechanisms responsible.
... In the last two decades, several investigations using IET have reported significant reductions in RBP in normotensive (Ray & Carrasco, 2000;Howden et al., 2002;McGowan et al., 2007a;Devereux et al., 2010Devereux et al., , 2012Wiles et al., 2010;Badrov et al., 2013a), prehypertensive (Wiley et al., 1992;Peters et al., 2006;Millar et al., 2008;Baross et al., 2012), and hypertensive adults (Taylor et al., 2003;Peters et al., 2006;McGowan et al., 2007b;Badrov et al., 2013b;Millar et al., 2013a). IET has also been reported as effective in multiple groups, for example, in the young (McGowan et al., 2007a;Devereux et al., 2010Devereux et al., , 2012Badrov et al., 2013a), the aged (Taylor et al., 2003;McGowan et al., 2007b;Baross et al., 2012;Badrov et al., 2013b;Millar et al., 2013a), and both men (Devereux et al., 2010(Devereux et al., , 2012Wiles et al., 2010;Baross et al., 2012) and women (Taylor et al., 2003;Millar et al., 2008;Badrov et al., 2013a,b). ...
... IET has also been reported as effective in multiple groups, for example, in the young (McGowan et al., 2007a;Devereux et al., 2010Devereux et al., , 2012Badrov et al., 2013a), the aged (Taylor et al., 2003;McGowan et al., 2007b;Baross et al., 2012;Badrov et al., 2013b;Millar et al., 2013a), and both men (Devereux et al., 2010(Devereux et al., , 2012Wiles et al., 2010;Baross et al., 2012) and women (Taylor et al., 2003;Millar et al., 2008;Badrov et al., 2013a,b). Thus far, the most common IET protocols have comprised isometric handgrip (IHG; Wiley et al., 1992;Taylor et al., 2003;McGowan et al., 2006;McGowan et al., 2007a,b;Millar et al., 2008;Stiller-Moldovan et al., 2012;Badrov et al., 2013a,b;Millar et al. 2013a) or bilateral leg (IBL; Howden et al., 2002;Devereux et al., 2010;Wiles et al., 2010;Devereux et al., 2011;Baross et al., 2012;Devereux et al., 2012) training, with 4 × 2-min contractions at ∼20-50% maximal voluntary contraction (MVC) and 1-5-min rest between sets. ...
... The design of IET programs may be an important factor in CV responses and adaptations that reportedly result. In a number of IET studies, training-induced hypotensive effects were evident after 3-4 weeks of training 3 days/week using either IHG (Wiley et al., 1992;Badrov et al., 2013a) or IBL (Howden et al., 2002;Devereux et al., 2010) modes of IET. Further, Wiley et al. (1992) performed two different IET experiments, one of which demonstrated reductions in BP at 4 weeks, the other at 3 weeks performing IHG training. ...
Hypertension is a major health concern, and current recommendations for blood pressure management (lifestyle modifications and pharmacological intervention) have not been universally successful. For two decades, isometric exercise training (IET) has become established as effective at reducing in resting BP (RBP) in a short period (4–10 weeks). The most common IET modes have comprised isometric handgrip (IHG) or isometric bilateral leg (IBL) training and 4 × 2-min contractions at ∼20–50% maximal voluntary contraction with 1–5-min rest between. Although this type of exercise training could have important implications, for hypertensive patients and in preventing hypertension development, little is known about the mechanisms responsible for IET-induced RBP reductions. This uncertainty derives from a lack of understanding concerning the most effective IET programs for specific populations. Possible influential factors and mechanisms include age, sex, pre-existing disease and medication, and IET-induced adaptations in the exercising muscle and nervous system, which are discussed in this review. Designing effective IET programs may involve manipulation of exercise intensity, frequency, duration and mode, as well as consideration of yet discovered mechanisms for RBP reductions. We call for additional research designed to understand more about the mechanisms involved in IET-induced RBP reductions for maximum effectiveness.
... Meanwhile, in another meta-analysis study conducted by Cornelissen and Smart [6], the largest reductions in resting BP were reported following the isometric resistance exercise training (systolic: -10.9 ± 2.86 mmHg), diastolic: -6.2 ± 3.34 mmHg) compared to after endurance (systolic: -3.5 ± 6.01 mmHg, diastolic: -3.7 ± 3.92 mmHg) and dynamic resistance exercise training (systolic: -1.8 ± 4.85 mmHg, diastolic: -2.5 ± 3.29 mmHg). It has been suggested that an isometric exercise training protocol consisting of four sets of 2-minute handgrip [7,8] or leg contractions [9] at 30-50% of maximal voluntary contraction (MVC) [2,10] with 1-4 minutes of passive rest between each contraction [2,7] aldosterone stimulating peptide, besides activating bradykinin, a potent vasodilator that leads to a drop in BP [24]. Hence, given that the ACE I/D gene polymorphism has an important role in BP regulation, the BP response to exercise training may vary among individuals with different genotypes of ACE I/D gene polymorphism. ...
... Besides resting BP and HR, the present study also showed that 8 weeks of IHG training significantly improved muscle strength ( Table 2). The increase in muscle strength observed in the present study is consistent with results of previous studies demonstrating that IHG exercise at 30% of MVC improved muscle strength [9,54]. ...
... Meanwhile, in another meta-analysis study conducted by Cornelissen and Smart [6], the largest reductions in resting BP were reported following the isometric resistance exercise training (systolic: -10.9 ± 2.86 mmHg), diastolic: -6.2 ± 3.34 mmHg) compared to after endurance (systolic: -3.5 ± 6.01 mmHg, diastolic: -3.7 ± 3.92 mmHg) and dynamic resistance exercise training (systolic: -1.8 ± 4.85 mmHg, diastolic: -2.5 ± 3.29 mmHg). It has been suggested that an isometric exercise training protocol consisting of four sets of 2-minute handgrip [7,8] or leg contractions [9] at 30-50% of maximal voluntary contraction (MVC) [2,10] with 1-4 minutes of passive rest between each contraction [2,7] aldosterone stimulating peptide, besides activating bradykinin, a potent vasodilator that leads to a drop in BP [24]. Hence, given that the ACE I/D gene polymorphism has an important role in BP regulation, the BP response to exercise training may vary among individuals with different genotypes of ACE I/D gene polymorphism. ...
... Besides resting BP and HR, the present study also showed that 8 weeks of IHG training significantly improved muscle strength ( Table 2). The increase in muscle strength observed in the present study is consistent with results of previous studies demonstrating that IHG exercise at 30% of MVC improved muscle strength [9,54]. ...
We examined the association between the angiotensin I-converting enzyme (ACE) I/D gene polymorphism and isometric handgrip (IHG) training on cardiovascular and muscular responses among normotensive males. Thirty (II = 10, ID = 10, and DD = 10) normotensive untrained males underwent IHG training at 30% of their maximal voluntary contraction 3 days per week for 8 weeks. Cardiovascular and muscular variables were measured before IHG, after a session of IHG and after 8 weeks of IHG. No significant interaction effect was found between ACE I/D genotype and IHG training session on all dependent variables (all p > 0.05). There was a significant main effect of IHG training session on systolic blood pressure (SBP) (p = 0.002), mean arterial pressure (MAP) (p = 0.015) and handgrip strength (HGS) (p = 0.001) scores, while no difference in diastolic blood pressure (DBP), pulse pressure, or heart rate scores was found. A greater improvement in cardiovascular parameters following 8 weeks of IHG training was observed in participants with the D allele than the I allele (SBP reduction: ID+DD genotype group (-5.53 ± 6.2 mmHg) vs. II genotype group (-1.52 ± 5.3 mmHg)); MAP reduction: ID + DD genotype group (-2.80 ± 4.5 mmHg) vs. II genotype group (-1.45 ± 3.5 mmHg). Eight weeks of IHG training improved cardiovascular and muscular performances of normotensive men. Reduction in SBP and MAP scores in D allele carriers compared to I allele carriers indicates that the ACE I/D polymorphism may have an influence on IHG training adaptation in a normotensive population.
... 5,6 Over the past 2 decades, isometric exercise training (IET) has become established as effective at inducing substantial reductions in resting blood pressure (RBP) in a short period. [7][8][9][10][11][12] Furthermore, typical IET investigations use either handgrip or double-leg exercise protocols, with participants and investigators meeting in the laboratory for periods of 3 to 10 weeks. [7][8][9]11,13,14 Albeit effective, time and travel requirements for participants as well as time spent by researchers have been significant, which is impractical for implementing IET at the population level, especially for extended periods (>10 weeks). ...
... [7][8][9][10][11][12] Furthermore, typical IET investigations use either handgrip or double-leg exercise protocols, with participants and investigators meeting in the laboratory for periods of 3 to 10 weeks. [7][8][9]11,13,14 Albeit effective, time and travel requirements for participants as well as time spent by researchers have been significant, which is impractical for implementing IET at the population level, especially for extended periods (>10 weeks). Even when a short duration exercise program such as IET is administered, travel requirements, access to specialized equipment, and associated costs may outweigh the perceived potential benefits (eg, RBP reduction) of the intervention. ...
Isometric exercise training (IET)–induced reductions in resting blood pressure (RBP) have been achieved in laboratory environments, but data in support of IET outside the laboratory are scarce. The aim of this study was to compare 12 weeks of home-based (HOM) IET with laboratory-based, face-to-face (LAB) IET in hypertensive adults. Twenty-two hypertensive participants (24–60 years) were randomized to three conditions: HOM, LAB, or control (CON). IET involved isometric handgrip training (4 × 2 minutes at 30% maximum voluntary contraction, 3 days per week). RBP was measured every 6 weeks (0, 6, and 12 weeks) during training and 6 weeks after training (18 weeks). Clinically meaningful, but not statistically significant reductions in RBP were observed after 12 weeks of LAB IET (resting systolic blood pressure [SBP] −9.1 ± 4.1; resting diastolic blood pressure [DBP] −2.8 ± 2.1; P >.05), which was sustained for 6 weeks of detraining (SBP −8.2 ± 2.9; DBP −4 ± 2.9, P >.05). RBP was reduced in the HOM group after 12 weeks of training (SBP −9.7 ± 3.4; DBP −2.2 ± 2.0; P >.05), which was sustained for an additional 6 weeks of detraining (SBP −5.5 ± 3.4; DBP −4.6 ± 1.8; P >.05). Unsupervised home-based IET programs present an exciting opportunity for community-based strategies to combat hypertension, but additional work is needed if IET is to be used routinely outside the laboratory.
... All eligible participants were recruited and randomized in a crossover design to a 4-week IET intervention or control period separated by a 3-week washout period. Previous de-training data demonstrated that the significant BP reductions following IET were mitigated within 10 days following the final session, which suggests 3 weeks will constitute a sufficient washout period (Howden et al., 2002). Block randomization was performed via Microsoft Excel. ...
Isometric exercise training (IET) is an effective intervention for the management of resting blood pressure (BP). However, the effects of IET on arterial stiffness remain largely unknown. Eighteen unmedicated physically inactive participants were recruited. Participants were randomly allocated in a cross-over design to 4 weeks of home-based wall squat IET and control period, separated by a 3-week washout period. Continuous beat-to-beat hemodynamics, including early and late systolic (sBP 1 and sBP 2, respectively) and diastolic blood pressure (dBP) were recorded for a period of 5 min and waveforms were extracted and analyzed to acquire the augmentation index (AIx) as a measure of arterial stiffness. sBP 1 (-7.7 ± 12.8 mmHg, p = 0.024), sBP 2 (-5.9 ± 9.9 mmHg, p = 0.042) and dBP (-4.4 ± 7.2 mmHg, p = 0.037) all significantly decreased following IET compared to the control period. Importantly, there was a significant reduction in AIx following IET (-6.6 ± 14.5%, p = 0.02) compared to the control period. There were also adjacent significant reductions in total peripheral resistance (-140.7 ± 65.8 dynes·cm-5, p = 0.042) and pulse pressure (-3.8 ± 4.2, p = 0.003) compared to the control period. This study demonstrates an improvement in arterial stiffness following a short-term IET intervention. These findings have important clinical implications regarding cardiovascular risk. Mechanistically, these results suggest that reductions in resting BP following IET are induced via favorable vascular adaptations, although the intricate details of such adaptations are not yet clear.
... Leg volume (LV) is an important reference in nutrition (Villaça et al. 2008;Wilson et al. 2013), physiology in exercise (Davies 1974;Winter et al. 1991;Marsh et al. 1999;Howden et al. 2002;Carvalho et al. 2011;Marillier et al. 2021), or clinical diagnosis in medicine, such as evaluation of lymphedema or vascular malformations (Mayrovitz 2012;Podleska et al. 2014;Williams and Whitaker 2015;Suehiro et al. 2015;Cau et al. 2016;Yahathugoda et al. 2017;Gianesini et al. 2019;Speir et al. 2019;Fink et al. 2021). Therefore, how to evaluate LV easily and quickly with accuracy is important in these areas. ...
Background
Leg volume (LV) is an important reference in nutrition, physiology in exercise, or clinical diagnosis. Therefore, how to evaluate LV easily and quickly with accuracy is important in these areas.
Aim
To develop a simple anthropometric estimation formula with ease of use and good accuracy for leg volume (LV) of female labourers.
Subjects
One hundred and thirty female labourers (110 subjects for formula regression procedure and 20 subjects for the comparison phase) were recruited as subjects with no reported leg surgery history, trauma, or deformity.
Methods
A set of 3 D scanners was used to measure the range data of each subject’s leg.
Results
The resultant LV estimation formula is LV = 0.215 × LL × CTH1.620 with R² = 0.967, in which LL stands for leg length and CTH for circumference of thigh. Mean error of this LV estimation is 0.10% and much smaller than that of the previous study (25.11% with significant difference).
Conclusion
An anthropometric estimation formula for female labourers’ leg volume was developed in this study. Estimation mean error of this formula is much smaller than the one in the previous study. This formula is easy to use and shows good accuracy in estimating female labourers’ leg volume.
... High blood pressure is one of the main causes of heart and vascular disorders. Whelton et al. [18] and Howden [19] et al. suggested aerobic exercise to reduce blood pressure in both hypertensive and normotensive persons. In a study conducted on 1675 university students, a direct relationship between elevated systolic blood pressure and body mass index (BMI) was found [20]. ...
Background:
A decrease in physical activity levels among university students during the COVID-19 pandemic is well-documented in the literature. However, the effect of lockdown restrictions on cardiovascular fitness has not been thoroughly investigated.
Methods:
The aim of the study was to assess the possible changes in cardiovascular fitness among university students during a 14-week period of the COVID-19 pandemic. Thirteen female and seven male tourism and recreation students participated in the study. Examinations were conducted in November 2020 and in February/March 2021. Students performed the PWC170 test on a cycling ergometer. Maximal oxygen consumption was calculated based on the PWC170 test results. Blood pressure and heart rate were measured at rest, as well as in the 1st and 5th minute of post-exercise recovery.
Results:
No substantial changes were observed in maximal oxygen consumption level when comparing autumn and winter indices. Male students presented elevated blood pressure whereas female students presented normal blood pressure. Heart-rate and blood-pressure indices did not show substantial alternations in examined students during analyzed period.
Conclusions:
Fourteen weeks of lockdown had little effect on the cardiovascular health of tourism and recreation students.
... Por otra parte, el entrenamiento isométrico clasificado con un nivel de evidencia C por la American Hearth Asociation (AHA) y considerado como un tratamiento complementario, al parecer demanda un mayor cuerpo de investigación, ya que sus efectos sobre las diferentes variables hemodinámicas, metabólicas y las que describen la condición endotelial no son suficientemente conocidos. (8,9,10,11) Algunos estudios muestran que la condición de fuerza prensil está asociada con disminución del riesgo cardiometabólico y específicamente con una disminución de la presión arterial en diferentes poblaciones. (12,13,14,15) Lo anterior adquiere importancia, al saber que la edad y los niveles de presión sanguínea determinan el 70 % de la varianza de la rigidez arterial. ...
Efectos del entrenamiento de fuerza prensil y su asociación sobre la función vascular en sujetos con criterios diagnósticos de síndrome metabólico: una revisión de tema Revista Cubana de Investigaciones Biomédicas 2022; 41:e1411 RESUMEN Introducción: Diversos estudios han demostrado que la fuerza prensil se asocia con una menor mortalidad cardiovascular y no cardiovascular en diferentes poblaciones. Objetivo: Describir los efectos del entrenamiento de la fuerza prensil y su asociación sobre la función vascular de sujetos con criterios diagnósticos de síndrome metabólico a través de una revisión de tema. Método: Se realizó búsqueda bibliográfica en Web of Science, Pubmed, Scopus, Embase, Sciencedirect, de ensayos clínicos controlados, estudios observacionales, de corte transversal o revisiones sistemáticas, publicadas en inglés, portugués y español, que evaluaron parámetros de rigidez arterial e incluyeron como evaluación o tratamiento la fuerza prensil en sujetos que presentaran por lo menos un criterio diagnóstico de síndrome metabólico. Resultados: De los 69 artículos encontrados, tres cumplieron con los criterios de inclusión. La totalidad de los documentos analizados incluyeron población hipertensa; uno de ellos mostró asociación indirecta entre la máxima contracción isométrica voluntaria, el índice de rigidez arterial y el índice de aumento al 75 %. Otro evidenció disminución de la presión arterial sin cambios en la función vascular posterior a un entrenamiento de fuerza isométrica prensil. Conclusión: La evidencia que describe los efectos del entrenamiento isométrico y la asociación de la fuerza prensil sobre la función vascular es escasa. La literatura analizada muestra una relación entre la condición de la fuerza prensil y parámetros de rigidez arterial periférica en sujetos con hipertensión. Este entrenamiento parece no mejorar la condición vascular en sujetos hipertensos. Palabras claves: fuerza prensil; síndrome metabólico; presión arterial; ejercicio. ABSTRACT Introduction: Several studies have shown that prehensile strength is associated
... Por otra parte, el entrenamiento isométrico clasificado con un nivel de evidencia C por la American Hearth Asociation (AHA) y considerado como un tratamiento complementario, al parecer demanda un mayor cuerpo de investigación, ya que sus efectos sobre las diferentes variables hemodinámicas, metabólicas y las que describen la condición endotelial no son suficientemente conocidos. (8,9,10,11) Algunos estudios muestran que la condición de fuerza prensil está asociada con disminución del riesgo cardiometabólico y específicamente con una disminución de la presión arterial en diferentes poblaciones. (12,13,14,15) Lo anterior adquiere importancia, al saber que la edad y los niveles de presión sanguínea determinan el 70 % de la varianza de la rigidez arterial. ...
RESUMEN Introducción: Diversos estudios han demostrado que la fuerza prensil se asocia con una menor mortalidad cardiovascular y no cardiovascular en diferentes poblaciones. Objetivo: Describir los efectos del entrenamiento de la fuerza prensil y su asociación sobre la función vascular de sujetos con criterios diagnósticos de síndrome metabólico a través de una revisión de tema. Método: Se realizó búsqueda bibliográfica en Web of Science, Pubmed, Scopus, Embase, Sciencedirect, de ensayos clínicos controlados, estudios observacionales, de corte transversal o revisiones sistemáticas, publicadas en inglés, portugués y español, que evaluaron parámetros de rigidez arterial e incluyeron como evaluación o tratamiento la fuerza prensil en sujetos que presentaran por lo menos un criterio diagnóstico de síndrome metabólico. Resultados: De los 69 artículos encontrados, tres cumplieron con los criterios de inclusión. La totalidad de los documentos analizados incluyeron población hipertensa; uno de ellos mostró asociación indirecta entre la máxima contracción isométrica voluntaria, el índice de rigidez arterial y el índice de aumento al 75 %. Otro evidenció disminución de la presión arterial sin cambios en la función vascular posterior a un entrenamiento de fuerza isométrica prensil. Conclusión: La evidencia que describe los efectos del entrenamiento isométrico y la asociación de la fuerza prensil sobre la función vascular es escasa. La literatura analizada muestra una relación entre la condición de la fuerza prensil y parámetros de rigidez arterial periférica en sujetos con hipertensión. Este entrenamiento parece no mejorar la condición vascular en sujetos hipertensos.
... The importance of these findings is substantial [49] considering a 10 mmHg reduction in systolic BP and 5-mmHg reduction in diastolic BP is associated with a 40% lower risk of stroke and 30% lower risk of mortality from heart disease and other vascular causes throughout middle age [6]. Although we have consistently demonstrated that IE can lower BP [10,37,38,50], interpretation of the results, along with the findings of others is limited by small participant numbers [9,10,37,[51][52][53][54][55][56]. Isometric exercise may provide a new viable solution with respect to exercise for those with stage 1 hypertension, but evidence for the efficacy of IE in this clinical population is still not robust. ...
Background
Hypertension (HTN) affects approximately 25% of the UK population and is a leading cause of mortality. Associated annual health care costs run into billions. National treatment guidance includes initial lifestyle advice, followed by anti-hypertensive medication if blood pressure (BP) remains high. However, adoption and adherence to recommended exercise guidelines, dietary advice and anti-hypertensive medication is poor. Four short bouts of isometric exercise (IE) performed 3 days per week (d/wk) at home elicits clinically significant reductions in BP in those with normal to high-normal BP. This study will determine the feasibility of delivering personalised IE to patients with stage 1 hypertension for whom lifestyle changes would be recommended before medication within NHS primary care.
Methods
This is a randomised controlled feasibility study. Participants were 18+ years, with stage 1 hypertension, not on anti-hypertensive medication and without significant medical contraindications. Trial arms will be standard lifestyle advice (control) or isometric wall squat exercise and standard lifestyle advice. Primary outcomes include the feasibility of healthcare professionals to deliver isometric exercise prescriptions in a primary care NHS setting and estimation of the variance of change in systolic BP. Secondary outcomes include accuracy of protocol delivery, execution of and adherence to protocol, recruitment rate, attrition, perception of intervention viability, cost, participant experience and accuracy of home BP. The study will last 18 months. Sample size of 100 participants (50 per arm) allows for 20% attrition and 6.5% incomplete data, based upon 74 (37 each arm) participants (two-sided 95% confidence interval, width of 1.33 and standard deviation of 4) completing 4 weeks. Ethical approval IRAS ID is 274676.
Discussion
Before the efficacy of this novel intervention to treat stage 1 hypertension can be investigated in any large randomised controlled trial, it is necessary to ascertain if it can be delivered and carried out in a NHS primary care setting. Findings could support IE viability as a prophylactic/alternative treatment option.
Trial registration
ISRCTN13472393 , registered 18 August 2020
... Tilt table testing is widely used in clinical laboratories and/or in teaching to assess effects of central hypovolemia. Head up tilt table-induced changes in systemic and cerebral vascular resistance have been shown to be similar to those that occur during LBNP (3). In laboratories where LBNP and medical supervisions are available, LBNP can be used as a teaching tool for simulating central hypovolemia in physiology and medical school curricula. ...
In this paper we assessed how lower body negative pressure (LBNP) can be used to teach students the physiological effects of central hypovolemia in the absence of the LBNP and/or a medical monitor using a "dry lab" activity using LBNP data that have been previously collected. This activity was performed using published LBNP papers, with which students could explore LBNP as an important tool to study physiological responses to central hypovolemia as well as consider issues in performing an LBNP experiment and interpreting experimental results. The activity was performed at the All India Institute of Medical Sciences, New Delhi, with 31 graduate students and 4 teachers of physiology. Both students and teachers were provided with a set of questionnaires that inquired about aspects related to the structure of the activity and how this activity integrated research and knowledge, as well as aspects related to motivation of the students and teachers to perform the activity. Our results from student and teacher surveys suggest that a "dry lab" activity using LBNP to teach physiology can be an important tool to expose students to the basics of systems physiology as well as to provide useful insights into how research is performed. Providing insight into research includes formulating a research question and then designing (including taking into account confounding variables), implementing, conducting, and interpreting research studies. Finally, developing such an activity using LBNP can also serve as a basis for developing research capacities and interests of students even early in their medical studies.
... The one most recent systematic review with meta-analysis that was included is described in detail elsewhere [12]. Briefly, this study [12] included 16 randomised controlled trials conducted in five different countries (United Kingdom, Canada, United States, Australia, Germany) with a total of 492 men and women (266 IE, 226 control) [27,[47][48][49][50][51][52][53][54][55][56][57][58][59][60]. As reported in the original meta-analysis [12], study quality using the Physiotherapy Evidence Database (PEDro) scale averaged 5.9 (range ¼ 4-8), with high scores representing better study quality. ...
Purpose
Isometric exercise (IE) has been shown to reduce resting systolic blood pressure (SBP) and diastolic blood pressure (DBP) in adults. However, no one to date has determined whether true inter-individual response differences (IIRD) versus random variability exist with respect to IE and resting SBP and DBP in adults ≥18 years of age. The purpose of the current study was to address this gap.
Methods and materials
Using the meta-analytic approach, randomised controlled trials from a recent meta-analysis that examined the effects of IE on resting SBP and DBP were included. Change outcome standard deviations for SBP and DBP from IE and control groups were used to calculate true IIRD from each study. The inverse variance heterogeneity (IVhet) model was used to pool results.
Results
Pooled changes for true IIRD in SBP (16 studies, 411 participants) were 3.3 mmHg (95% confidence interval, −3.1 to 5.6 mmHg) while tau (τ) was 4.2. For DBP, true IIRD (16 studies, 411 participants) were 2.3 mmHg (95% confidence interval, −0.7 to 3.3 mmHg) while tau (τ) was 2.2. The 95% prediction interval for true IIRD in a future study was −5.8 to 7.4 mmHg for SBP and −2.7 to 4.2 mmHg for DBP. The percent chance, i.e. probability, of a clinically meaningful difference of 2 mmHg was 68% for SBP and 75% for DBP, both of which were only considered as ‘possibly clinically important’.
Conclusion
While IE reduces resting SBP and DBP in adults, the results of the current study suggest that random variability versus true IIRD account for any potential differences as a result of IE on changes in resting SBP and DBP in adults. Thus, a search for potential moderators and mediators, including potential genetic interactions associated with IE, may not be warranted.
... The importance of these ndings is substantial considering a 10 mmHg reduction in systolic BP and 5 mmHg reduction in diastolic BP is associated with a 40% lower risk of stroke and 30% lower risk of mortality from heart disease and other vascular causes throughout middle age (20). Although we have consistently demonstrated that IE can lower BP (19,(21)(22)(23), interpretation of the results, along with the ndings of others is limited by small participant numbers (18)(19)(23)(24)(25)(26)(27)(28)(29). Isometric exercise may provide a new viable solution with respect to exercise for those with Stage 1 hypertension, evidence for the e cacy of IE in this clinical population is still not robust. ...
Background: Hypertension (HTN) affects approximately 25% of the UK population and is a leading cause of mortality. Associated annual health care costs run into billions. National treatment guidance includes initial lifestyle advice, followed by anti-hypertensive medication if blood pressure (BP) remains high. However, adoption and adherence to recommended exercise guidelines, dietary advice and anti-hypertensive medication is poor. Four short bouts of isometric exercise (IE) performed 3 days per week (d/wk) at home elicits clinically significant reductions in BP in those with normal to high-normal BP. This study will determine the feasibility of delivering personalised IE to patients with Stage 1 hypertension for whom lifestyle changes would be recommended before medication within NHS primary care.
Methods: This is a randomised controlled feasibility study. Participants 18+ years, with Stage 1 hypertension, not on anti-hypertensive medication and without significant medical contraindications. Trial arms will be standard lifestyle advice (control) or isometric wall squat exercise and standard lifestyle advice. Primary outcomes include success of intervention delivery and change in BP. Secondary outcomes include accuracy of protocol delivery, execution of and adherence to protocol, recruitment rate, attrition, perception of intervention viability, cost, participant experience, and accuracy of home BP. The study will last 18 months. Sample size of 100 participants (50 per arm) allows for 20% attrition and 6.5% incomplete data, based upon 74 (37 each arm) participants (two-sided 95% confidence interval, width of 1.33 and standard deviation of 4) completing 4 weeks. Ethical approval IRAS ID: 274676.
Discussion: Before the efficacy of this novel intervention to treat Stage 1 hypertension can be investigated in any large randomised controlled trial, it is necessary to ascertain if it can be delivered and carried out in a NHS primary care setting. Findings could support IE viability as a prophylactic / alternative treatment option.
Trial Registration: International Standard Randomised Controlled Trial Number (ISRCTN) 13472393 registered 18 August 2020. http://www.isrctn.com/ISRCTN13472393
... Howden y Fisher, 2002 indicaron que los mecanismos asociados con la hipotensión después del entrenamiento es una combinación de aumento de la vasodilatación debido a la inhibición presináptica de los nervios vasoconstrictores y la activación elevada del receptor de histamina. Las disminuciones medidas centralmente se deben a la "retirada" del sistema nervioso simpático y el restablecimiento inducido aferente muscular del barorreflejo 25 . Estos mecanismos alterarían tanto el gasto cardíaco como la resistencia vascular periférica 26,27 . ...
Effect of hand grip strength training of ascending intensity on blood pressure and muscle oxygenation kinetics in elderly people with hypertension type l
... Previous studies showed that IET decreases resting BP (5)(6)(7)(8); conversely, few studies have demonstrated interindividual variability or the lack of IET effect on BP (9,10). Three studies that aimed to predict resting BP reduction induced by IET showed that the assessment of cardiovascular reactivity to acute isometric exercise or serial subtraction would be useful (11)(12)(13). ...
Objective: Isometric resistance training may reduce resting blood pressure (BP); however, the magnitude of this effect varies among individual subjects and few studies attempted to predict it. This study aimed to investigate the potential hypotensive effects of isometric training and their association with cardiovascular reactivity to acute isometric exercise and muscle strength in young women.
Methods: In this randomized trial, twenty young women were randomly assigned to either the training (n = 10) or control (n = 10) group. Women from the training group performed unilateral isometric handgrip sessions for 8 weeks (4 × 2 min at 25% of maximal voluntary contraction [MVC]; 3 days/week). Cardiovascular reactivity to acute isometric exercise and MVC were measured at baseline. Resting BP was assessed during and after the intervention.
Results: Resting systolic BP significantly lowered only in the training group. The change in resting systolic BP following an 8-week intervention was significantly associated with the systolic BP and diastolic BP reactivity to the acute exercise at baseline during set 3 and 4 (P <.05). The handgrip MVC was associated with changes in systolic BP (r = 0.79, P =.007), diastolic BP (r = 0.68, P =.032), and mean arterial pressure (r = 0.79, P =.006). These results indicated that high cardiovascular reactivity and strength attenuate the hypotensive effects following isometric training in young women.
Conclusions: The hypotensive effects following isometric training may be identified by BP reactivity to acute isometric exercise or handgrip strength in young women.
... According to Howden R et al. in 2002, studied the efforts of isometric exercises training on rsting blood pressure and orthostatic tolerance in humans, was evaluated on 27 subjects 9 training or control group) performed 5 weeks of isometric exercise training of the legs, and after an 8 weeks intervening period, a 2 nd training group (6 subjects) undertook 5 weeks of isometric arm training. It was concluded that lower resting blood pressure is probably not responsible for the increased orthostatic tolerance after isometric training of the legs. ...
The McKenzie exercises revolves around a system of classification to accurately diagnose the cause of patient's pain.. The studies have indicate that all forms of exercise seem to be effective in reduction B.P. The study design was an experimental study and conducted in girls hostel of Guru Jambheshwar University of science and technology, Hisar. The study was carried out on 80 normal subjects consisting of healthy young females of different age groups. Subjects who are hypertensive, Subjects with low back pain pathology and non-cooperative patients were excluded.The result of this study shows that the repetitive McKenzie lumbar flexion exercises in standing position (FIS) showed a statistically significant difference in comparison with other McKenzie lumbar spine exercises (Flexion in standing, extension in lying and Extension in standing). There is no statistically significant difference between FIL, EIL and EIS McKenzie exercises. Repetitive McKenzie lumbar flexion exercises in standing position has a marked dynamic stress on the cardiovascular system of normal individuals in comparison with other McKenzie exercises i.e. Flexion in lying, Extension in lying, and Extension in standing. During the 1960's , Robin McKenzie developed his own examination and treatment methods for spinal disorders, and is now recognized internationally as an authority on the diagnosis and treatment of low back pain. The McKenzie method is not just extension exercises. In its reality, McKenzie is a comprehensive approach to the spine based on good principles. The central theory of McKenzie's principles was the concept that spinal extension was a primary technique for pain management. The main tent of the McKenzie technique is a concept known as centralization whereby the patient attempts to extend his or her muscles in such a way that the pain experienced goes back to the center of the back. Centralized back pain is preferable to pain that radiates away to the legs, stomach, or shoulders. The McKenzie exercises revolves around a system of classification to accurately diagnose the cause of patient's pain. The three classifications are postural in which problems caused due to the stress of soft-tissue caused by incorrect posture, dysfunction in which pain caused due to tissue being shortened because of scars, and Derangement in which there is change in the position of the vertebra due to fluid imbalances in the discs. McKenzie Technique is non-specific and significant changes occurs within 10-15 repetitions and numbers of times in a day. It varies according to the syndrome to be treated, the effect to be obtained and the capability of the patient. Exercise should be performed with almost continuous rhythm. On each contraction, the maximum possible range must be maintained for a second or two followed by relaxation and a brief pause of only a fraction of a second. The McKenzie method is based on finding a cause and effect relationship between the positions the patient usually has while sitting, standing or moving and the generation of pain as a result of those positions or activities. The McKenzie assessment is a comprehensive and logical step by step process to evaluate the patient's problem quickly. Mckenzie exercises helps to reduce pain in the back by stretching the spine and surrounding muscles. Mckenzie treatment prescribes a series of individualized exercises. The exercises are as-follows-lying prone, extension in lying, sustained extension, extension in standing, extension mobilization, extension manipulation, rotation mobilisation in extension, rotation manipulation in extension, sustained rotation/mobilisation in flexion, rotation manipulation in flexion, rotation manipulation in flexion, flexion in lying, flexion in standing, flexion in step-standing, correction of lateral-shift, self-contraction of lateral-shift. McKenzie treatment uniquely emphasizes education and active patient involvement in the management of their treatment in order to decrease pain Indian J.Sci.Res. 08 (2): 91-97, 2018
... Despite this, numerous IE modalities have been used to elicit BP reductions. Most common among these exercises is IHG [20][21][22][23][24][25][26][27]39,41,66 ; however, both single leg and double leg extension have also been used to significantly reduce BP, [33][34][35]44,67,68 with other, more novel, exercises also appearing in the literature, for instance, Howden et al 68 found isometric arm curls efficacious at reducing BP, Bentley et al- 36,69 noting significant BP reductions with a high-intensity handgrip and MINT protocols and Wiles et al 30 noting significant reductions following an isometric wall squat intervention. This variety of IE used in the previous research alludes to the plausibility that a multiexercise isometric program may be efficacious at reducing BP as well as having a positive influence on adherence rates. ...
Background: Hypertension is the leading risk factor for global mortality. Isometric resistance exercise training reduces blood pressure (BP). However, the protocols used are often limited by cost/immobility and the use of rigid exercise modalities. In response, a novel more versatile, isometric exercise (IE) device, the IsoBall (IB) was created. Purpose: The aim of this study was to test the BP-lowering effectiveness of this prototype. Methods: Twenty-three healthy participants (29.10±2.19 years old, 173.95±3.83 cm, 75.43±5.06 kg, SBP 127.10±10.37 mmHg, DBP 70.40±6.77 mmHg) were randomly allocated to either a control group (CON) or 2 isometric handgrip (IHG) training groups that used the Zona plus (ZON) and IB devices. The intervention groups completed 3 sessions each week of 4, 2 min IHG at 30% maximal voluntary contraction, with a 1-min rest, for 4 weeks. Resting BP, heart rate (HR) and IHG strength were measured in all groups at baseline and postintervention. Results: Postintervention systolic BP (SBP) was significantly lower in both ZON (114.5±8.2 mmHg, p = 0.000) and IB (119.9±7.0 mmHg, p = 0.000) compared to control (131.0±12.4 mmHg). Postintervention diastolic BP (DBP) was reduced in both intervention groups (ZON 66.6±7.4 mmHg, p = 0.004; IB 65.7±10.0 mmHg, p = 0.012) compared to CON (71.1±8.8 mmHg). Mean arterial pressure (MAP) was reduced in both groups (ZON 82.6±6.8 mmHg, p = 0.000; IB 84.3±9.1 mmHg, p = 0.000) compared to control (91.0±9.7 mmHg). No significant changes were seen in HR or strength (p > 0.05). Conclusion: The results of this study indicate that both the ZON and IB devices elicit significant SBP, DBP and MAP reductions. Despite the ZON group having larger reductions in BP, no significant differences were found between the two devices. Thus, this study indicates the IB device to be an effective alternative to the ZON that can also be used to perform other IE modalities.
... Unlike dynamic resistance exercise that involves movement at the joints, the isometric resistance exercise does not require any movement of the affected joint and the muscle length will remain unchanged (57). Over several years, numerous studies have studied the role of isometric resistance exercise training in reducing blood pressure (26)(27)(28)(29)(30)(58)(59)(60). In fact, a current meta-analysis study reported that the reduction in resting blood pressure had been largest following isometric resistance exercise training (systolic: -10.9 mmHg, diastolic: -6.2 mmHg) compared to endurance (systolic: -3.5 mmHg, diastolic: -3.7 mmHg) and dynamic resistance exercise training (systolic: -1.8 mmHg, diastolic: -2.5 mmHg) (44). ...
Exercise has been suggested as the best and the most affordable way for managing blood pressure. The insertion/ deletion of angiotensin I-converting enzyme (ACE) I/D gene polymorphism had been reported to be linked with several diseases such as hypertension and diabetic nephropathy. Several studies showed that blood pressure response to exercise training for health management also vary among individuals with different genotypes of ACE I/D gene poly-morphism. A study of 9 months of endurance exercise training at 75 to 85 % of VO 2 max showed that the decrease of resting blood pressure in I allele carriers wass greater than D allele carriers. In contrast, other study discovered that adult women with D allele had greater reduction in resting blood pressure than those with I allele, following a 12-week combined aerobic and resistance exercise training. Despite the inconsistencies of some findings, it has remained unknown if the ACE I/D gene polymorphism would also influence blood pressure response to isometric handgrip training that had been found to be superior to the dynamic resistance exercise training in controlling and preventing high blood pressure. Thus, this article was to review the literature on ACE I/D gene polymorphism and blood pressure response to exercise training that could serve as the basis for future research to identify individuals who will lower resting blood pressure the most with exercise training program for health management.
... The exercise-induced increase in tolerance time during orthostatic stress has been shown to not occur in subjects with high baseline orthostatic tolerance, and appears to be positively correlated with the magnitude of the exercise-induced increase in plasma volume, with the existence of a threshold of 150 mL, above which there is a clinically meaningful decrease in OI [97,98]. Notably, orthostatic tolerance has been reported to increase after resistance exercise training of the lower limbs, rather than after resistance exercise training of the upper limbs [102,103]. The decreased baroreflex sensitivity during orthostatic stress as a result of chronic exercise training has been convincingly demonstrated to be induced by exercise-induced hypervolemia, possibly reflecting less need for the recruitment of baroreflex mechanisms in the context of hypervolemia-induced attenuation of orthostatic stress [97,98,104]. ...
The most frequent cause of syncope in young athletes is noncardiac etiology. The mechanism of noncardiac syncope (NCS) in young athletes is neurally-mediated (reflex). NCS in athletes usually occurs either as orthostasis-induced, due to a gravity-mediated reduced venous return to the heart, or in the context of exercise. Exercise-related NCS typically occurs after the cessation of an exercise bout, while syncope occurring during exercise is highly indicative of the existence of a cardiac disorder. Postexercise NCS appears to result from hypotension due to impaired postexercise vasoconstriction, as well as from hypocapnia. The mechanisms of postexercise hypotension can be divided into obligatory (which are always present and include sympathoinhibition, histaminergic vasodilation, and downregulation of cardiovagal baroreflex) and situational (which include dehydration, hyperthermia and gravitational stress). Regarding postexercise hypocapnia, both hyperventilation during recovery from exercise and orthostasis-induced hypocapnia when recovery occurs in an upright posture can produce postexercise cerebral vasoconstriction. Athletes have been shown to exhibit differential orthostatic responses compared with nonathletes, involving augmented stroke volume and increased peripheral vasodilation in the former, with possibly lower propensity to orthostatic intolerance.
... Small-scale research studies have demonstrated the powerful effect isometric exercise training (IET) has on reducing resting blood pressure (BP), with mean reductions of between 10 and 13 mm Hg systolic and 6 and 8 mm Hg for diastolic reported (1). Evidence suggests that an IET mode using larger compared with smaller muscle mass is able to produce a similar magnitude of resting BP reduction when conducted at significantly lower exercise intensity (2). Moreover, statistically significant reductions may occur at a faster rate, taking 3 wk after leg extension exercise (3) compared with 4-5 wk reported for hand grip exercise (4). ...
ABSTRACT Isometric exercise training (IET) effectively reduces resting blood pressure (BP). Traditionally, IET protocols use hand grip or leg extension exercise. IET using larger muscle mass may influence the rate and magnitude of BP reductions. This study aimed to examine the efficacy of a novel isometric wall squat protocol. Twenty participants completed four laboratory visits over 2 wk. Two incremental isometric wall squat exercise (IWSE) tests were completed to determine the relationship of knee joint angle to heart rate (HR) and BP. The incremental IWSE test started at 135° of knee flexion decreasing by 10° every 2 min until 95° (final stage). Exercise was terminated upon completion of the 10-min test or at volitional fatigue. To ascertain the efficacy of prescribing IWSE training, the relationship between knee joint angle and mean HR was used to calculate the participant-specific knee joint angle required to elicit a target HR of 95% HRpeak for 2× IWSE training sessions. There were inverse relationships (P < 0.05) between knee joint angle and mean HR/BP parameters (r ≥ −0.99), with no difference in the peak HR during the last 30 s of the two incremental tests (P > 0.05). Although there were no differences (P > 0.05) in mean HR and BP values between repeated training sessions, there were differences (P < 0.05) within and between the four bouts during a session. In conclusion, data indicate that the IWSE test provides a reliable means of prescribing and monitoring isometric exercise intensity. The ability of IWSE to reduce resting BP when used for isometric exercise training prescription has been demonstrated in healthy participants. This finding could be significant in the nonpharmacological prevention, treatment, and management of hypertension.
... There was no association between duration of intervention and BP reduction. Hand grip exercise seems to be superior to that of leg press exercise in hypertensive subjects (Howden et al., 2002). 3 sessions per week is superior to that of 5 sessions per week (Badrov et al., 2013a) and followed by most of the studies. ...
... Evidence for the blood pressure (BP) lowering effects of isometric exercise is growing (Börjesson et al. 2016). To date, studies have reported that isometric exercise lowers BP in healthy adults (Wiley et al. 1992;Ray and Carrasco 2000;Howden et al. 2002;Millar et al. 2008;Wiles et al. 2010;Devereux et al. 2011;Badrov et al. 2013a;Devereux and Wiles 2015;Gill et al. 2015), hypertensive (non-medicated and medicated), and pre-hypertensive adults (Wiley et al. 1992;Taylor et al. 2003;McGowan et al. 2006McGowan et al. , 2007bPeters et al. 2006; Baross et al. 2012Baross et al. , 2013Millar et al. 2013;Badrov et al. 2013b). Due to the mounting evidence, The American Heart Association is the first organisation to recommend Communicated by Massimo Pagani. ...
PurposeIsometric exercise (IE) has been shown to lower blood pressure (BP). Using equipment with force output displays, intensity is usually regulated at 30% maximal voluntary contraction (MVC); however, the cost of programmable equipment and their requirement for maximal contractions presents limitations. A simple, cost-effective alternative deserves investigation. The purpose of this study was (1) to explore the relationship between %MVC, change in systolic BP (ΔSBP), and perceived exertion (CR-10) and (2) to assess the validity of self-regulation of intensity during isometric hand-grip exercise. Methods
Fourteen pre-hypertensive and hypertensive adults completed eight, 2-min isometric hand-grip exercises at randomised intensities; participants estimated their perceived exertion at 30-s intervals (estimation task). Subsequently, on three separate occasions, participants performed four 2-min contractions at an exertion level that they perceived to be equivalent to CR-10 “Level-6” (production task). ResultsThere were significant linear relationships between the estimated exertion on the CR-10 scale, and ΔSBP (r = 0.784) and %MVC (r = 0.845). Level-6 was equivalent to an average ΔSBP of 38 mmHg (95% CI; 44, 32 mmHg) and a relative force of 33% MVC (95% CI; 36.2, 30%). During the production task, %MVC was not significantly different between the estimation task and each production trial. In at least the first two repetitions of each production trial, ΔSBP was significantly lower than that observed in the estimation task. Conclusion
These findings show that CR-10 “Level-6” is an appropriate method of self-regulating isometric hand-grip intensity; its use offers an affordable and accessible alternative for isometric exercise prescription aimed at reducing BP.
... There was no association between duration of intervention and BP reduction. Hand grip exercise seems to be superior to that of leg press exercise in hypertensive subjects (Howden et al., 2002). 3 sessions per week is superior to that of 5 sessions per week (Badrov et al., 2013a) and followed by most of the studies. ...
Aim: To systematically review and report the articles on isometric exercise on blood pressure. Method: Study was done on February 2016 in Google Scholar using search terms 'Isometrics' and 'Blood pressure' AND 'India'. 420 articles were initially identified and after inclusion, exclusion criteria 3 articles are used for this review.Results: Studies were at least 5 weeks duration with 30% MVIC (maximum voluntary isometric contraction) of intensity for 3 min duration. Total of 110 subjects participated with median of 30 subjects. Garg et al. (2014) found mean difference (MD) of-9.87 mmHg in SBP and-5.26 mmHg in DBP. Sandhu et al. (2014) found MD of-7.04 mmHg in SBP and-6.56 mmHg in DBP. Gandhi (2016) found MD of-3.24 mmHg in SBP and-4.03 mmHg in DBP. Overall there was a mean reduction of 6.72 mmHg in SBP and 5.28 mmHg in DBP. Conclusion: After isometric exercise in Indians BP reduction is as of Western counterparts.
... Studies in the past had focused on determining the BP and heart rate responses to different forms of exercises and the population studied were normal healthy individuals [11,13,17,19,20]. A few studies even used isometric hand grip exercise as a measure to determine the response of BP in comparatively normal healthy subjects [18,[21][22][23]. Philip J Millar [24] presented with a narrative review of Isometric hand grip effects on Hypertension. ...
Abstract: This study aims to determine gender differences in response of blood pressure (BP) to isotonic handgrip
exercise (IHG) in prehypertensive adolescents. In addition, it also aims to determine differences in recovery patterns of
BP and pulse rate (PR) between genders. 60 volunteers with prehypertension (male–30; female–30) participated in this
study. Resting systolic (SBP) and diastolic blood pressure (DBP) and PR of participants were recorded on arrival after 5
minutes of rest. This was followed by IHG for 20 minutes and BP, PR variables were recorded. Measurements were
again recorded into the follow up period after 60 minutes. Independent t-test (p<0.05) was used to compare means of
SBP, DBP, PR, mean arterial pressure (MAP) and Pulse pressure (PP) between male and female participants at rest, after
20 minutes of IHG exercise and 60 minutes post exercise. Male participants had higher resting SBP and PP as compared
to their female counterparts, whereas resting values of DBP, PR and MAP were higher in females. Significant differences
were observed between genders in DBP (p=0.012), PR (p=0.024), MAP (p=0.033) and PP (p=0.022) 20 minutes after
IHG exercise except SBP (p=0.723).Similarly 60 minutes post exercise, male and female participants showed significant
differences in DBP (p=0.009), PR (p=0.002), MAP (p=0.011) and PP (p=0.028) except SBP (p=0.507). Decline of SBP,
DBP, MAP and PP were higher in males whereas decline in PR was high in females. These results suggest existence of
gender differences in BP response to isotonic hand grip exercise in prehypertensives.
Keywords: Prehypertensives, Isotonic handgrip exercise, Blood pressure, Pulse rate, Recovery pattern, Gender
differences.
... Results of the present study were similar to that of (Mortimer & Mckune, 2011) who reported significant decrease in blood pressure after isometric exercise training for 5 consecutive days in older people. Numerous studies have used isometric exercise training to induce reductions in resting blood pressure in both healthy participants and hypertensive patients (Howden, Lightfoot, Brown, & Swaine, 2002;Taylor, McCartney, Kamath, & Wiley, 2003;McGowan, Levy, McCartney, & MacDonald, 2007;Millar, Bray, McGowan, MacDonald, & McCartney, 2007;Stiller-Moldovan, Kenno, & McGowan, 2012). Studies suggested that the significant reduction observed in SBP after isometric exercise training was due to the reduction in sympathetic nerve activity (Pescatello et al., 2004). ...
How to cite this article: Al Kitani, M. (March, 2017). Blood pressure responses to isometric handgrip training in normal healthy female students. ABSTRACT The objective of the study was to determining the effect of isometric handgrip training program on blood pressure in sedentary young female students and to compare and find the differences between the control group and the experimental group. Thirty-nine untrained female students participated in this study (Age 18.47±0.51). After taking resting measures, the experimental group were required to perform an isometric hand grip strength contraction with one hand for 45 seconds at 30% of maximal voluntary contraction. Four repeated isometric contraction was required (two per hand) with total of 3 minutes of exercise per session. Measurements of HR and BP were taken immediately before the first 45 seconds contraction, and immediately after the 4 th contraction and after 3 minutes of sitting period. There were no significant differences between the groups in terms of age, body mass, height, resting heart rate, systolic blood pressure and diastolic blood pressure. However, there were significant differences between the groups for the maximal voluntary contraction between pre and post intervention. Isometric handgrip training may reduce resting heart rate and blood pressure in Omani female adults.
... Isometric handgrip training (IHG) has been the most commonly prescribed IE training intervention, possibly because of mobility issues with some older and physically inactive adults. However, research has suggested that a larger muscle mass may influence the magnitude of BP reductions (14). As such, other groups have utilized isometric leg training (46), which has produced notable reductions in BP, of a similar level to IHG training, even when performed at a lower relative percentage of maximal voluntary contraction (26). ...
Purpose:
Elevated arterial blood pressure (BP) is associated with autonomic dysfunction and impaired haemodynamic control mechanisms. Isometric exercise (IE) training has been demonstrated effective at reducing BP; however, the continuous cardiovascular responses during IE are underinvestigated. We hypothesized that reflex autonomic cardiovascular control is an important mediator in reducing BP. To test our hypothesis, we investigated continuous cardiac autonomic modulation and baroreceptor reflex sensitivity (BRS) in response to IE.
Methods:
Twenty-five pre-hypertensive participants performed a single IE wall squat training session. Total power spectral density of heart rate variability (HRV) and associated low frequency (LF) and high-frequency (HF) power spectral components, were recorded in absolute (ms) and normalised units (nu) pre, during and post an IE session. Heart rate (HR) was recorded via electrocardiography and BRS via the sequence method. Continuous blood pressure was recorded via the vascular unloading technique and stroke volume via impedance cardiography. Total peripheral resistance (TPR) was calculated according to Ohm's Law.
Results:
During IE there were significant reductions in HRV (p<0.05) and BRS (p<0.05) and significant increases in HR (p<0.001), systolic, diastolic, and mean BP (all p<0.001). In recovery from IE, HRV (p<0.001) HFnu (p<0.001) and BRS (p<0.001) significantly increased with a significant decrease in LFnu (p<0.001) and LF:HF ratio (p<0.001), indicative of predominant parasympathetic over sympathetic activity. This autonomic response was associated with a significant reduction in systolic (23.2?18.1 mmHg, p<0.001), diastolic (18.7 ? 16.9 mmHg, p<0.001) and mean (15.8?15.5 mmHg, p<0.001) BP, below baseline and a significant reduction in TPR (p<0.001).
Conclusions:
A single IE session is associated with improved cardiac autonomic modulation and haemodynamic cardiovascular control in pre-hypertensive males. These acute responses may be mechanistically linked to the chronic reductions in resting BP reported following IE training interventions.
... Previous studies conducting isometric handgrip training at 30% MVC produced conflicting results. Some small studies have failed to show DBP reductions; Howden et al [27] who had 8 participants conducting 5 weeks of IRT and Taylor et al [28] with 9 participants after 10 weeks of IRT, saw no statistical reductions in DBP with baseline <85 mmHg. In contrast, both single studies [29] and pooled analyses from several studies [2,8,10] have shown significant reductions in DBP after IRT. ...
Introduction
Hypertension is a major risk factor contributing to cardiovascular disease, which is the number one cause of deaths worldwide. Although antihypertensive medications are effective at controlling blood pressure, current first-line treatment for hypertension is nonpharmacological lifestyle modifications. Recent studies indicate that isometric resistance training (IRT) may also be effective for assisting with blood pressure management. The aim of this study was to determine the efficacy of IRT for blood pressure management and the suitability of a low-intensity working control group.
Methods
Forty hypertensive individuals, aged between 36 and 65 years, conducted IRT for 8 weeks. Participants were randomized into 2 groups, working at an intensity of either 5% or 30% of their maximum voluntary contraction. Participants performed 4 × 2 minute isometric handgrip exercises with their nondominant hand, each separated by a 3-minute rest period, 3 days a week.
Results
Blood pressure measurements were conducted at baseline and at the end of the protocol using a Finometer. Eight weeks of isometric resistance training resulted in a 7-mmHg reduction of resting systolic blood pressure (SBP) (136 ± 12 to 129 ± 15; P = 0.04) in the 30% group. Reductions of 4 mmHg were also seen in mean arterial pressure (MAP) (100 ± 8 to 96 ± 11; P = 0.04) in the 30% group. There were no statistically significant reductions in diastolic blood pressure for the 30% group, or any of the data for the 5% group.
Conclusion
Isometric resistance training conducted using handgrip exercise at 30% of maximum voluntary contraction significantly reduced SBP and MAP. A lack of reduction in blood pressure in the 5% group indicates that a low-intensity group may be suitable as a working control for future studies.
... It has been recognised for many years that tremor can be an accompanying feature of peripheral neuropathy 110 111 . In immune neuropathies, tremor is found more often than not in patients with IgM paraproteinaemic neuropathy (IgMPN) [111][112][113] , in patients with CIDP 114 and in the recovery phase of Guillain-Barré syndrome 115 although there is lack of a larger scale prospective assessment of this. ...
This thesis describes a series of studies involving patients with neuropathies and healthy controls. In the studies of disease, two groups were recruited: patients with inflammatory neuropathies and those with hereditary neuropathies. Each group was separated into those with and those without tremor and compared with healthy controls. Clinical assessments and neurophysiological tests were employed to correlate cerebellar function with tremor. The final study of healthy participants investigated the effect of transcranial direct current stimulation (TDCS) on the cerebellum during finger tapping. 1) Tremor was most common in IgM paraproteinaemic neuropathies, also occurring in 58% of those with chronic inflammatory demyelinating polyradiculoneuropathy and 56% of those with multifocal motor neuropathy with conduction block (MMNCB). Tremor was generally refractory to treatment and contributed to disability in some patients. Although tremor severity correlated with F wave latency, it was insufficient to distinguish those with, from those without tremor. 2) Impaired eyeblink classical conditioning and paired associative stimulation in patients with inflammatory neuropathy and tremor differentiated them from neuropathy patients without tremor and healthy controls, strongly suggesting impairment of cerebellar function is linked to the production of tremor in these patients. 3) The prevalence study in CMT1A patients revealed tremor in 21% and in 42% of those it caused impairment. Eyeblink conditioning, visuomotor adaptation and electro-oculography were no different between tremulous and non-tremulous patients and healthy controls. This argues against a prominent role for an abnormal cerebellum in tremor generation in the patients studied. Rather, they suggest an enhancement of the central neurogenic component of physiological tremor as a possible mechanism. 4) TDCS of the lateral cerebellum and its effect on paced finger tapping was examined. There was no effect on accuracy or variability of the intertap interval, providing no support for a direct role of the cerebellum in event based timing.
... recently, a large and emerging body of evidence supports isometric resistance training as an effective exercise modality to lower resting BP in both normotensive and hypertensive populations (Wiley et al. 1992;Ray and Carrasco 2000;Howden et al. 2002;Taylor et al. 2003;Peters et al. 2006;McGowan et al. 2007a, b;Millar et al. 2008;Devereux et al. 2010;Wiles et al. 2010; Baross et al. 2012;Millar et al. 2013;Badrov et al. 2013a, b;Gill et al. 2015). Two recent meta-analyses suggest that isometric resistance training may be capable of eliciting greater BP reductions than traditional aerobic and resistance exercise training (Cornelissen and Smart 2013;Carlson et al. 2014). ...
Introduction
Isometric resistance training has repeatedly shown to be an effective exercise modality in lowering resting blood pressure (BP), yet associated mechanisms and sex differences in the response to training remain unclear. Exploration into potential sex differences in the response to isometric resistance training is necessary, as it may allow for more optimal and sex-based exercise prescription, thereby maximizing the efficacy of the training intervention.
Purpose
Therefore, we investigated, in normotensives, whether sex differences exist in the response to isometric handgrip (IHG) training.
Methods
Resting BP and endothelium-dependent vasodilation (brachial artery flow-mediated dilation; FMD) were assessed in 11 women (23 ± 4 years) and 9 men (21 ± 2 years) prior to and following 8 weeks of IHG training (four, 2-min unilateral contractions at 30 % of maximal voluntary contraction; 3 days per week).
Results
Main effects of time were observed (all P < 0.05), whereby IHG training reduced systolic BP (Δ 8 ± 6 mmHg), diastolic BP (Δ 2 ± 3 mmHg), mean arterial pressure (Δ 4 ± 3 mmHg), and pulse pressure (Δ 5 ± 7 mmHg), accompanied by increases in absolute (Δ 0.09 ± 0.15 mm) and relative (Δ 2.4 ± 4.1 %) brachial artery FMD; however, no significant sex differences were observed in the magnitude of post-training change in any variable assessed (all P > 0.05).
Conclusion
IHG training effectively lowers resting BP and improves endothelium-dependent vasodilation in men and women, without significant sex differences in the magnitude of response.
... Contrary to the findings of Wiles, Howden et al. (Howden et al. 2002) observed statistically significant reductions in SBP after 3 weeks of isometric leg exercise at ~20% MVC and after 4 weeks of isometric arm training at ~30% MVC. Furthermore, Gill et al.(Gill et al. 2014) hypothesised that reductions in resting BP from IET would be intensity dependent, they compared the effects of low (~23% MVC) and moderate (~34% MVC) IET over a 3 week period and reported a reduction in SBP in the moderate intensity group only. ...
There exists no examination of what is the minimum anti-hypertensive threshold intensity for isometric exercise training. Twenty two normotensive participants were randomly assigned to training intensities at either 5% or 10% of their maximal contraction. Twenty participants completed the study. Clinical meaningful, but not statistically significant, reductions in systolic blood pressure were observed in both 5% and 10% groups -4.04 mmHg (95% CI -8.67 to +0.59, p = 0.08) and -5.62 mmHg (95% CI -11.5 to +0.29, p = 0.06) respectively after 6 weeks training. No diastolic blood pressure reductions were observed in either 5% -0.97 mmHg (95% CI -2.56 to +0.62, p = 0.20) or 10%MVC +1.8 mmHg (95%CI -1.29 to +4.89, p = 0.22) groups respectively after training. In those unable to complete isometric exercise at the traditional 30% intensity, our results suggest there is no difference between 5 and 10% groups and based on the principle of regression to the mean, this could mean both interventions induce a similar placebo-effect.
... Isometric Arm Counter-Pressure Maneuvers (IACPM) [17] is a recent therapeutic approach to impede VVS and prevent the patient from losing consciousness. The basic concept is that a hypotensive status is always present during the prodromal phase preceding the syncope and is caused by peripheral vasodilatation due to the inhibition of sympathetic vasoconstrictive activity. ...
High blood pressure (BP) is a global health challenge. Isometric resistance training (IRT) has demonstrated antihypertensive effects, but safety data are not available, thereby limiting its recommendation for clinical use. We conducted a systematic review of randomized controlled trials comparing IRT to controls in adults with elevated BP (systolic ≥130 mmHg/diastolic ≥85 mmHg). This review provides an update to office BP estimations and is the first to investigate 24-h ambulatory BP, central BP, and safety. Data were analyzed using a random-effects meta-analysis. We assessed the risk of bias with the Cochrane risk of bias tool and the quality of evidence with GRADE. Twenty-four trials were included (n = 1143; age = 56 ± 9 years, 56% female). IRT resulted in clinically meaningful reductions in office systolic (–6.97 mmHg, 95% CI –8.77 to –5.18, p < 0.0001) and office diastolic BP (–3.86 mmHg, 95% CI –5.31 to –2.41, p < 0.0001). Novel findings included reductions in central systolic (–7.48 mmHg, 95% CI –14.89 to –0.07, p = 0.035), central diastolic (–3.75 mmHg, 95% CI –6.38 to –1.12, p = 0.005), and 24-h diastolic (–2.39 mmHg, 95% CI –4.28 to –0.40, p = 0.02) but not 24-h systolic BP (–2.77 mmHg, 95% CI –6.80 to 1.25, p = 0.18). These results are very low/low certainty with high heterogeneity. There was no significant increase in the risk of IRT, risk ratio (1.12, 95% CI 0.47 to 2.68, p = 0.8), or the risk difference (1.02, 95% CI 1.00 to 1.03, p = 0.13). This means that there is one adverse event per 38,444 bouts of IRT. IRT appears safe and may cause clinically relevant reductions in BP (office, central BP, and 24-h diastolic). High-quality trials are required to improve confidence in these findings. PROSPERO (CRD42020201888); OSF (https://doi.org/10.17605/OSF.IO/H58BZ).
Isometric exercise training (IET) is an effective method for reducing resting blood pressure (BP). To date, no research studies have been conducted using multiple exercises within an IET intervention. Previous research has suggested that varied exercise programmes may have a positive effect on adherence. Therefore, this randomized controlled study aimed to investigate the BP-lowering efficacy of a multi-modal IET (MIET) intervention in healthy young adults. Twenty healthy participants were randomized to an MIET [n = 10; four women; SBP 117.9 ± 6.9 mmHg; DBP 66.3 ± 5.1 mmHg] or control (CON) group (n = 10; five women; SBP, 123.3 ± 10.4 mmHg; DBP, 77.3 ± 6.7 mmHg). The MIET group completed three sessions per week of 4, 2-min isometric contractions, with a 1-min rest between each contraction, for 6 weeks. Resting BP and heart rate (HR) were measured at baseline and post-intervention. Pre-to-post intervention within-group reductions in resting BP were observed (SBP: 5.3 ± 6.1 mmHg, DBP: 3.4 ± 3.7 mmHg, MAP: 4.0 ± 3.9 mmHg, HR: 4.8 ±6 .6 bpm), although clinically relevant (≥2 mmHg), these changes were not statistically significant. Significant (p < 0.05) between-group differences were found between the intervention and control groups, indicating that the MIET intervention has a greater BP-lowering effect compared to control. The clinically relevant post-training reductions in resting BP suggest that MIET may be a promising additional IET method for hypertension prevention. These findings; however, must be interpreted with caution due to the small sample size and the non-clinical cohort.
Background and method:
This meta-analysis sought to: quantify the effects of isometric resistance training (IRT) on the magnitude of change in systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and resting heart rate in adults; and examine whether the magnitude of change in SBP, DBP, MAP and heart rate was different with respect to the patient demographic characteristics and IRT parameters. To be included in the meta-analysis, studies had to be randomized controlled trials lasting 2 or more weeks, investigating the effects of IRT on blood pressure in adults. The methodological quality of the studies selected was evaluated using the PEDro scale. For each main outcome measure, an average effect size and its respective 95% confidence intervals were calculated.
Results:
A total of 16 articles (492 participants) fulfilled the selection criteria (mean quality score in the PEDro scale of 5.9). Compared with control groups, IRT groups showed statistically significant (P < 0.05) and clinically relevant (>2 mmHg) positive effects on the SBP (-5.23 mmHg) and MAP (-2.9 mmHg). IRT groups also showed statistically significant, but not clinically relevant reduction in DBP (-1.64 mmHg). Furthermore, IRT groups did not report any statistically significant and clinically relevant (>5 bpm) effect on resting heart rate (-0.08 bpm).
Conclusion:
The analysis of moderator variables showed that none of them exhibited a statistically significant relationship with the positive effects of IRT for lowering blood pressure. Therefore, IRT may be considered an appropriate nonpharmacologic treatment for lowering SBP and MAP.
Background:
This work aimed to explore whether different forms of a simple isometric exercise test could be used to predict the blood pressure (BP)-lowering efficacy of different types of isometric resistance training (IRT) in healthy young adults. In light of the emphasis on primary prevention of hypertension, identifying those with normal BP who will respond to IRT is important. Also, heightened BP reactivity increases hypertension risk, and as IRT reduces BP reactivity in patients with hypertension, it warrants further investigation in a healthy population.
Methods:
Forty-six young men and women (24 ± 5 years; 116 ± 10/ 68 ± 8 mmHg) were recruited from two study sites: Windsor, Canada (n=26; 13 women), and Northampton, United Kingdom (n=20; 10 women). Resting BP and BP reactivity to an isometric exercise test were assessed prior to and following 10 weeks of thrice weekly IRT. Canadian participants trained on a handgrip dynamometer (isometric handgrip, IHG), while participants in the UK trained on an isometric leg extension dynamometer (ILE).
Results:
Men and women enrolled in both interventions demonstrated significant reductions in systolic BP (P<0.001) and pulse pressure (PP; P<0.05). Additionally, test-induced systolic BP changes to IHG and ILE tests were associated with IHG and ILE training-induced reductions in systolic BP after 10 weeks of training, respectively (r= 0.58 and r=0.77; for IHG and ILE; P<0.05).
Conclusions:
The acute BP response to an isometric exercise test appears to be a viable tool to identify individuals who may respond to traditional IRT prescription.
Depletion of leg lean mass has been progressively recognised as an important clinical outcome in disease populations, being related to early disability, impaired health-related quality of life, and even mortality. Estimation of leg lean volumes (LLV) from circumferences and skinfold thicknesses, in particular, have long been used as these techniques are inexpensive and widely-available in clinical settings. The truncated cones method proposed by Jones and Pearson (1967) might be particularly useful for clinical populations in which loss of leg lean mass is common, usually as part of the cachexia syndrome (e.g., chronic heart failure, chronic obstructive pulmonary disease (COPD), chronic renal failure, liver failure, sepsis, rheumatoid arthritis, AIDS and cancer). The method divides the leg into six segments which are assumed to represent truncated cones. Summation of the volume of each cone, determined from the circumferences and the height of each individual cone, gives an estimate of total LV. By subtracting the skinfold thicknesses from the circumferences, a lean volume of each cone can be derived, thereby providing an estimate of LLV. Despite its obvious advantages compared to more sophisticated and costier approaches, the method is time-consuming, needs careful standardization and a trained observer. Moreover, it is technically difficult to be performed in bed-bound patients, being influenced by oedema and obesity. More importantly, however, skinfold thickness measurements are obtained only at few selected locations and it is assumed that they are invariant across the lower limbs and not influenced by gender-specific patterns of fat tissue deposition. Notwithstanding these limitations, there is limited evidence that the method might be highly sensitive to indicate depletion of metabolic active tissue and its functional consequences in specific clinical populations, such as those with chronic obstructive pulmonary disease (COPD). Additional studies are warranted to extrapolate these findings for other disease populations with different levels of nutritional impairment.
Habitual and purposeful physical activity has been touted as an important part of prevention, treatment, and control of hypertension by the American College of Sports Medicine, American Heart Association, and by the seventh and eighth Joint National Committees for Reports on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (BP). However, little information has been disseminated on how exercise modality influences the resting BP response to regular exercise (training). Hypertension is closely associated with aging, insulin resistance, and sarcopenia. Resistance training (RT) is considered the exercise modality of choice for the delay or prevention of the adverse consequences of sarcopenia, and is also effective for reducing the risk of insulin resistance, as well as other risk factors for age-related diseases. Because of these favorable relationships, it is important to determine the effects of RT on BP, particularly in those at risk or who already have hypertension. Therefore, the purposes of this chapter are to describe: (1) the acute and chronic effects of RT on BP; (2) how these effects compare to those of aerobic exercise training; (3) how the effects of dynamic RT compare to those of static (isometric) RT on BP; and (4) whether there is an evidence-based rationale for developing an individualized exercise prescription for the use of RT in the prevention, treatment, and control of hypertension.
Introduction:
Cardiovascular deconditioning apparently progresses with flight duration, resulting in a greater incidence of orthostatic intolerance following long-duration missions. Therefore, we anticipated that the proportion of astronauts who could not complete an orthostatic tilt test (OTT) would be higher on landing day and the number of days to recover greater after International Space Station (ISS) than after Space Shuttle missions.
Methods:
There were 20 ISS and 65 Shuttle astronauts who participated in 10-min 80° head-up tilt tests 10 d before launch, on landing day (R+0), and 3 d after landing (R+3). Fisher's Exact Test was used to compare the ability of ISS and Shuttle astronauts to complete the OTT. Cox regression was used to identify cardiovascular parameters associated with OTT completion and mixed model analysis was used to compare the change and recovery rates between groups.
Results:
The proportion of astronauts who completed the OTT on R+0 (2 of 6) was less in ISS than in Shuttle astronauts (52 of 65). On R+3, 13 of 15 and 19 of 19 of the ISS and Shuttle astronauts, respectively, completed the OTT. An index comprised of stroke volume and diastolic blood pressure provided a good prediction of OTT completion and was altered by spaceflight similarly for both astronaut groups, but recovery was slower in ISS than in Shuttle astronauts.
Conclusions:
The proportion of ISS astronauts who could not complete the OTT on R+0 was greater and the recovery rate slower after ISS compared to Shuttle missions. Thus, mission planners and crew surgeons should anticipate the need to tailor scheduled activities and level of medical support to accommodate protracted recovery after long-duration microgravity exposures. Lee SMC, Feiveson AH, Stein S, Stenger MB, Platts SH. Orthostatic intolerance after ISS and Space Shuttle missions. Aerosp Med Hum Perform. 2015; 86(12, Suppl.):A54-A67.
Objective: To observe the short- term and staged effects of circuit/isometric resistence training on systolic blood pressure(SBP) and diastolic blood pressure(DBP) in patients with mild hypertension. Method: Fifty- seven patients with mild essential hypertension were randomly divided into circuit resistence training (CRT) group (n=28) and isometric resistence training (IRT) group (n=29). Patients of two groups performed three stages circuit resistence training and isometric resistence training respectively. Before each stage, one repetition maximum (1RM) load of patients was measured by resistance training equipment. All patients were trained with the intensity of 30% 1RM for upper limb and 50% 1RM for lower limb. Training methods were as follows: each time training for 20min, 3 times a week, each stage for 4 weeks, the whole process included 12 weeks. SBP and DBP were recorded at the moment of 15min before training, the end of training and 15min, 30min, 60min after training. Result: The mean value of SBP and DBP had no significant difference (P>0.05) between two groups at 3d before training. After training, the short-term effects on SBP declined gradually in all stages of CRT group. In IRT group, the short-term effects on SBP rose at the end of the training and declined gradually after training. The short-term effects on DBP of two groups rose at the end of training and declined gradually after training. In three stages, all patients SBP and DBP of each period showed a downward trend. Additionally, in the third stage of training, the SBP of IRT group decreased significantly than that of CRT group in 15min before training and 30min after training (P<0.05). Although, in the third stage of training, the DBP of two groups decreased significantly than before and at the first stage of training (P<0.05), there was no significant difference between them(P>0.05). Conclusion: CRT and IRT can make SBP and DBP of patients with mild hypertension showed a downward trend both after staged training and during short time after training, and the IRT showed more obvious effect on the decrease of SBP.
Illustrated Talk, followed by questions, University College
Purpose:
The purpose of this study was twofold: (1) to investigate the effect of 4 weeks of bilateral-leg isometric exercise training on the immediate isometric post-exercise cardiovascular responses, and (2) to ascertain whether any changes in immediate post-exercise cardiovascular responses may be associated with training-induced adaptations in resting blood pressure.
Methods:
Thirteen normotensive males completed both isometric exercise training (IET) and control conditions, which were separated by 6 weeks. Participants performed a total of twelve training sessions; 4 × 2-min bilateral-leg isometric exercise bouts separated by 3-min rest periods, 3 days week(-1).
Results:
Four weeks of bilateral-leg IET resulted in a reduction in resting SBP (120 ± 12-115 ± 12 mmHg, p = 0.01). The intercept of the 5-min post-exercise systolic blood pressure slope was lower (p = 0.015) following the 4-week training intervention. Individual changes in immediate post-exercise response SBP were also significantly correlated with reductions in resting SBP following 4 weeks of training. There were significant differences in the slopes of the first vs. final post-exercise BRS response (p = 0.009), and the intercepts of the HRR slopes (p = 0.04) recorded during the 5-min post-exercise periods.
Conclusions:
Four weeks of IET altered immediate cardiovascular responses to an individual IET session. Altered immediate responses were also associated with training-induced reductions in resting SBP. To our knowledge, this is the first evidence suggesting that very short-term (immediate) cardiovascular responses may be important in defining chronic reductions in resting blood pressure following a period of IET.
Double-leg isometric training has been demonstrated to reduce resting blood pressure in young men when using electromyographic activity (EMG) to regulate exercise intensity. This study assessed this training method in healthy older (45-60 years.) men. Initially, 35 older men performed an incremental isometric exercise test to determine the linearity of the heart rate versus percentage peak EMG (%EMGpeak) and systolic blood pressure versus %EMGpeak relationship. Thereafter, 20 participants were allocated to a training or control group. The training group performed three double-leg isometric sessions per week for 8 weeks, at 85% of peak heart rate. The training resulted in a significant reduction in resting systolic (11 ± 8 mmHg, P < 0.05) and mean arterial (5 ± 7 mmHg, P < 0.05) blood pressure. There was no significant change in resting systolic blood pressure for the control group or diastolic blood pressure in either group (all P > 0.05). These findings show that this training method, used previously in young men, is also effective in reducing resting systolic and mean arterial blood pressure in older men.
The purpose of this investigation was to identify cardiovascular responses associated with tolerance to lower body negative pressure (LBNP). In this study, 18 men, ages 29-51 years, were categorized as high (HT) or low (LT) LBNP tolerant based on a graded presyncopal-limited LBNP exposure criterion of -60 mm Hg relative to ambient pressure. Groups were matched for physical characteristics and preLBNP cardiovascular measurements, with the exceptions of greater (p less than 0.05) end-diastolic volume and cardiac output in the HT group. During peak LBNP, cardiac output was similar (NS) in both groups, although the HT group displayed a greater heart rate (p less than 0.05). In both groups, venous return appeared to limit cardiac output resulting in decreased arterial pressure. Tolerance to LBNP did not appear solely dependent on the absolute amount of blood pooled in the legs since the HT group demonstrated a greater (p less than 0.05) peak LBNP-induced increase in midthigh-leg volume. Greater tolerance to LBNP was associated with a larger preLBNP cardiac output reserve and higher compensatory increases in heart rate and peripheral resistance.
The reproducibility of tolerance to lower-body negative pressure (LBNP) has not been assessed sufficiently. Furthermore, there has been confusion concerning the most appropriate index by which LBNP tolerance can be quantified. The purpose of this study was to assess the degree of reproducibility in pre-syncopal-symptom-limited LBNP (LBNPtol), using an LBNP chamber. Twenty physically active subjects [median age (range) 21 (18–27) years] underwent three successive LBNPtol tests with 72–120 h between each test. LBNPtol was quantified using the LBNP tolerance index (LTI; ΔmmHg·min), cumulative stress index (CSI; mmHg·min), duration of negative pressure (DNP) and maximum magnitude of negative pressure (MNP). Heart rate (f
c), systolic (SBP) and diastolic (DBP) blood pressures from the three repeated tests were compared during a control period. The changes from control to maximum response (f
c, SBP, DBP) during LBNP were also compared, and percentage changes in estimated blood volume were measured. There were no statistical differences between any of these comparisons (P>0.05). LTI and CSI were greater in the third test when compared to the first two tests (P0.05). Measures of LTI and CSI showed an acceptable level of reproducibility for the first two repeated tests. However, there was an increase in LBNPtol on the third successive exposure to LBNP. These findings have shown that it is possible to achieve reproducible measures of tolerance to LBNP when using a custom-built chamber. This only applies to a test-retest procedure. Furthermore, these data also suggest that DNP and MNP do not adequately reflect the differences shown in LBNP tolerance when using LTI and CSI as measures.
1. This study evaluated the contribution of carotid and cardiopulmonary baroreceptors to reflex splanchnic and forearm vascular adjustments during venous pooling in man. We compared ( a ) responses to lower body suction which produces venous pooling with ( b ) responses to lower body suction plus simultaneous application of neck suction. The rationale was that simultaneous application of neck suction, which stretches carotid baroreceptors, would minimize the contribution of carotid baroreceptors to circulatory adjustments produced by lower body suction.
2. Lower body suction at 40 mmHg decreased central venous pressure and arterial pulse pressure and increased forearm vascular resistance (plethysmography), splanchnic vascular resistance (indocyanine green dye clearance), and heart rate. Simultaneous application of neck suction prevented the tachycardia and most of the splanchnic vasoconstriction during lower body suction, but did not significantly attenuate the forearm vasoconstriction.
3. The major findings in this study are first, that the splanchnic vasoconstrictor response during venous pooling is mediated primarily through carotid baroreceptors, and secondly, that carotid and cardiopulmonary baroreceptors produce strikingly contrasting and non‐uniform regional vascular responses during venous pooling. Cardiopulmonary baroreceptors exert the predominant influence on forearm vascular resistance, but appear to have only a minor influence on splanchnic vascular resistance. Carotid baroreceptors produce most of the splanchnic vasoconstriction during venous pooling. but have a minor role in the forearm vasoconstriction.
The accuracy and performance of the A&D TM 2421, a new ambulatory blood pressure (BP) monitoring device using both the cuff-oscillometric method (O) and the Korotkoff sound method (K) were evaluated. The device was tested for accuracy under static and dynamic conditions by simultaneous comparison with two observers using a standard mercury column sphygmomanometer (standard method) and by the objective recording method (ORM). The performance of the device was also evaluated under ordinary ambulatory conditions. The mean differences in BP of standard method from K-method were -1.2 +/- 4.7 mm Hg systole and 1.3 +/- 4.7 mm Hg diastole (n = 323, mean +/- SD) and those of standard method from O-method were -0.4 +/- 5.3 mm Hg systole and 1.4 +/- 5.1 mm Hg diastole (n = 323). The agreement between each of the two methods of the device and the standard method was within 10 mm Hg for more than 90% of both systolic and diastolic readings. During bicycle exercise, the mean differences in BP of standard method from K-method were -3.4 +/- 4.8 mm Hg systole and 1.8 +/- 5.2 mm Hg diastole (n = 71) and those of standard method from O-method were -1.1 +/- 7.3 mm Hg systole and 1.7 +/- 7.8 mm Hg diastole (n = 67). There was a greater scatter in the individual comparisons of the device and the standard method during exercise, especially in diastolic BP. The relation between the device and ORM was almost similar to that between the device and the standard method.(ABSTRACT TRUNCATED AT 250 WORDS)
Eight young men underwent an 8-month endurance exercise training program. Prior to and following the training program, the subjects' maximal oxygen uptake (VO2max), total blood volume (TBV) and plasma volume (PV), tolerance to lower body negative pressure (LBNP) assessed by the cumulative stress index (CSI) to presyncope, and their hemodynamic responses to 0 to -45 torr LBNP was determined. Hemodynamic measures included rebreathe carbon dioxide cardiac output (Qc), heart rate (HR), directly measured arterial blood pressures (ABP), and strain gauge determination of forearm blood flow (FBF) and leg volume changes (delta LgV). Calculated values of stroke volume (SV), forearm, vascular resistance (FVR), and peripheral vascular resistance (PVR) were made. Following training, each subject had an increased VO2max (mean = +27.4%, P < 0.001), TBV (mean = +15.8%, P < 0.02), and PV (mean = +16.5%, P < 0.02) and each subject had a decreased tolerance to LBNP (mean CSI = -24%, P < 0.001). Stepwise linear regression identified that the major factors to significantly predict the decreased CSI pre- to post-training were a reduced response of PVR to LBNP from -15 to -45 torr (Model R2 = 0.853), the delta TBV (model R2 = 0.981), and the greater post-training reduction in SBP to LBNP of 0 to -45 torr (model R2 = 1.0). These data suggest that physiologic adaptations associated with the increased VO2max and TBV resulting from a prolonged endurance exercise training program can alter the reflex control of vasomotion and cardiac output during LBNP and reduce the LBNP tolerance.
Both rhythmic and "resistive" (weight lifting) exercise training can produce modest decreases in resting blood pressure. The next logical point along an exercise continuum consisting of different proportions of rhythmic and isometric efforts is a strictly isometric effort. The purpose of these studies was to assess the effects of isometric, handgrip exercise training on resting blood pressure. To avoid the extreme pressor responses elicited by fatiguing isometric efforts, the isometric exercise training used in this study consisted of brief handgrip contractions separated by rest periods. Modest repeated rises in systolic and diastolic pressures therefore served as the putative stimuli for training adaptations in resting blood pressures. Human subjects in study 1 trained with four, 2-min isometric handgrip contractions with 3-min rests between contractions. The intensity of the contractions was equal to 30% of their maximal effort for each day. The bouts of isometric exercise were performed three times per week for 8 wk. Study 2 training consisted of four contractions of 50% of maximum effort held for a duration of 45 s with 1-min rests. These were performed 5 d.wk-1 for 5 wk. In Study 1, all eight trained subjects had a significant decline in both systolic and diastolic resting blood pressures, with group averages of 12.5 and 14.9 mm Hg, respectively. Seven matched control subjects who did not train had no change in resting pressures. In study 2, subjects were trained in their home or workplace and experienced significant mean declines in resting systolic and diastolic pressures of 9.5 and 8.9 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)
A number of normal daily and athletic activities require isometric or static exercise. Such sports as weight lifting and other high-resistance activities are used by athletes to gain strength and skeletal muscle bulk. However, static exercise also causes significant increases in blood pressure, heart rate, myocardial contractility, and cardiac output. These changes occur in response to central neural irradiation, called central command, as well as a reflex originating from statically contracting muscle. Studies have demonstrated that blood pressure appears to be the regulated variable, presumably because the increased pressure provides blood flow into muscles that have compressed their arterial inflow as a result of increases in intramuscular pressure created by contraction. Thus, static exercise is characterized by a pressure load to the heart and can be differentiated from dynamic (isotonic) exercise, which involves a volume load to the heart. Physical training with static exercise leads to concentric cardiac, particularly left ventricular, hypertrophy, whereas training with dynamic exercise leads to eccentric hypertrophy. Furthermore, the magnitude of cardiac hypertrophy is much less in athletes training with static than dynamic exercise. Neither systolic nor diastolic function is altered by the hypertrophic process associated with static exercise training. Many of the energy requirements for static exercise, particularly during more severe levels of exercise, are met by anaerobic glycolysis because the contracting muscle becomes deprived of blood flow. Training with repetitive static exercise therefore causes little increase in oxygen transport capacity, so that maximal oxygen consumption is either not or only minimally increased. Peripheral cardiovascular adaptations also can occur in response to static exercise training. Although controversial, these adaptations include modest decreases in resting blood pressure, smaller increases in blood pressure during a given workload, increases in muscle capillary-to-fiber ratio, improved lipid and lipoprotein profiles, and increases in glucose and insulin responsiveness. Some of these adaptations also have been found in cardiac patients and hypertensive patients and without any concomitant cardiovascular complications. However, in both healthy individuals and those with cardiovascular disease, the manner in which resistance training is performed may dictate the extent to which these adjustments take place. Specifically, training that involves frequent repetitions of moderate weight (and hence contains dynamic components) seems to produce the most beneficial results.
The accuracy of the TM-2420 ambulatory blood pressure monitor (A&D Co, Japan) has been assessed by the indirect method according to the recommendations of the Association for the Advancement of Medical Instrumentation (AAMI). Ninety subjects (43 men and 47 women), aged 19-89 with a range of systolic blood pressures (SBP) of 81-211 mmHg and diastolic blood pressures (DBP) of 32-113 mmHg were studied. The monitor was compared with two observers using the Hawksley random zero sphygomomanometer. The standard deviation of the difference (SDD) between the observers was 3.0 mmHg for SBP and 2.3 mmHg for DBP. The mean differences between observers were -0.31 mmHg for SBP and 0.32 mmHg for DBP (both NS). The average of three readings for each subject recorded by the monitor was compared with the average of the simultaneous readings by the observers. The SDD was 7.2 mmHg for SBP and 5.5 mmHg for DBP (within the recommendations for accuracy). The differences between methods were -0.98 mmHg for SBP and 0.18 mmHg for DBP; these differences were not significant (NS). The monitor was also assessed against direct intra-brachial artery pressure in 12 subjects (36 readings). The mean difference between the monitor and simultaneous individual intra-arterial reading was -9.5 mmHg for SBP (P less than 0.001) and 3.7 mmHg for DBP (P less than 0.001). The SDD's between methods were 12 mmHg for SBP and 5.0 mmHg for DBP. Use of the monitor in general clinical practice in 100 patients was also assessed. The rate of errors was low (6.8%), and the device found to be acceptable.(ABSTRACT TRUNCATED AT 250 WORDS)
1. This study was undertaken to determine whether, in a group of patients complaining of recurrent syncopal attacks but with no apparent cause, there was evidence of abnormal cardiovascular reflex control.
2. The steady-state responses of blood pressure, heart rate and cardiac output to head-up tilting were determined in 67 patients using entirely ‘non-invasive’ methods. In some patients we also studied the immediate response of pulse interval to carotid baroreceptor stimulation by neck suction.
3. Two of the patients developed vasovagal attacks during the 20 min test period of head-up tilting. Eighteen others showed postural hypotension, defined as a fall in blood pressure to outside the limits of two sds from the mean values of age-related control subjects.
4. Patients who showed postural hypotension had a mean fall in cardiac output significantly larger than that in age-related control subjects. Responses in the non-hypotensive patients did not differ significantly from controls.
5. Stimulation of carotid baroreceptors resulted in significantly smaller responses of pulse interval in the patients defined as having postural hypotension compared with the non-hypotensive patients and with the age-related control subjects.
6. In some of the patients who did not show postural hypotension during the standard test, the duration of tilt was prolonged for up to 1 h. Five out of 26 patients developed vasovagal attacks. All the vasovagal patients showed an initial tachycardia and the response of pulse interval to neck suction was significantly larger than in the controls.
7. This study has shown that simple non-invasive tests of cardiovascular reflex function can divide patients with poor orthostatic tolerance into two groups: those with evidence of small reflex responses, associated with abnormally large falls in cardiac output during tilting, and those with evidence of overactive reflexes associated with the tendency to develop vasovagal syncope.
Isometric exercise produces a characteristic pressor increase in blood pressure which may be important in maintaining perfusion of muscle during sustained contraction. This response is mediated by combined central and peripheral afferent input to medullary cardiovascular centers. In normal individuals the increase in blood pressure is mediated by a rise in cardiac output with little or no change in systemic vascular resistance. However, the pressor response is also maintained during pharmacologic blockade or surgical denervation by increasing systemic vascular resistance. Left ventricular function is normally maintained or improves in normal subjects and cardiac patients with mild impairment of left ventricular contractility. Patients with poor left ventricular function may show deterioration during isometric exercise, although this pattern of response is difficult to predict from resting studies. Recent studies have shown that patients with uncomplicated myocardial infarction can perform submaximum isometric exercise such as carrying weights in the range of 30 to 50 lb without difficulty or adverse responses. In addition, many patients who show ischemic ST depression or angina during dynamic exercise may have a reduced ischemic response during isometric or combined isometric and dynamic exercise. Isometric exercises are frequently encountered in activities of daily living and many occupational tasks. Cardiac patients should be gradually exposed to submaximum isometric training in supervised cardiac rehabilitation programs. Specific job tasks that require isometric or combined isometric and dynamic activities may be evaluated by work simulation studies. This approach to cardiac rehabilitation may facilitate patients who wish to return to a job requiring frequent isometric muscle contraction. Finally, there is a need for additional research on the long-term effects of isometric exercise training on left ventricular hypertrophy and performance. The vigorous training regimens currently utilized by international class and professional athletes should stimulate longitudinal studies of physiologic and pathophysiologic outcomes of intense isometric exercise training programs.
1. The cardiovascular responses to passive upright tilting were determined in healthy human subjects of various ages using entirely ‘non-invasive’ techniques. Cardiac output was determined by a single breath method and arterial blood pressure by an automatic sphygmomanometer.
2. Steady-state responses were achieved within 4–6 min from the onset of the tilt and were maintained for at least 15 min.
3. The reproducibilities of the responses to tilting by 60°, expressed as two standard deviations of the differences between responses on two occasions (mean responses in parentheses), were: cardiac output ±0.70 (−1.41) litre/min, heart rate ±7.6 (+ 14.7) beats/min, systolic blood pressure ± 15.5 (+ 1.0), and diastolic blood pressure μ13.1 (+ 13.6)mmHg.
4. Tilting by 20° resulted in no significant responses but between 20° and 60° responses were linearly related to the angle of tilt.
5. Supine values and responses to tilting by 60° were compared in subjects in four age groups between 20 and 80 years. With increasing age, the supine values of cardiac output declined and those of arterial blood pressures increased. Responses of heart rate, cardiac output and diastolic pressure declined by increasing age. These results, obtained from a healthy population, provide reference values for comparison with individuals who may have deficient postural responses.
Leg compliance is "causally related with greater susceptibility" to orthostatic stress. Since peak O2 uptake (peak VO2) and muscle strength may be related to leg compliance, we examined the relationships between leg compliance and factors related to muscle size and physical fitness. Ten healthy men, 25-52 yr, underwent tests for determination of vascular compliance of the calf (Whitney mercury strain gauge), peak VO2 (Bruce treadmill), calf muscle strength (Cybex isokinetic dynamometer), body composition (densitometry), and anthropometric measurements of the calf. Cross-sectional areas (CSA) of muscle, fat, and bone in the calf were determined by computed tomography scans. Leg compliance was not significantly correlated with any variables associated with physical fitness per se (peak VO2, calf strength, age, body weight, or composition). Leg compliance correlated with calf CSA (r = -0.72, P less than 0.02) and calculated calf volume (r = -0.67, P less than 0.03). The most dominant contributing factor to the determination of leg compliance was CSA of calf muscle (r = -0.60, P less than 0.06), whereas fat and bone were poor predictors (r = -0.11 and 0.07, respectively). We suggest that leg compliance is less when there is a large muscle mass providing structural support to limit expansion of the veins. This relationship is independent of aerobic and/or strength fitness level of the individual.
The purpose of this investigation was to evaluate the effect of moderate (non-hypertensive) levels of muscle tension on the cardiovascular responses to progressive lower body negative pressure (LBNP) in eight healthy male volunteers. Subjects were presented with progressive LBNP to -50 torr or the occurrence of vasovagal symptoms during three different levels of electromyographic activity in the lower limbs represented by the relaxed state, 5 and 10% maximal voluntary contraction. The same procedure was also performed at the same three levels of electromyographic activity in the arms with concomitant relaxation of the abdomen and lower extremities. In 75% of the subjects, pre-syncopal reactions were observed during the relaxed state while no pre-syncopal responses occurred during the elevated muscle tension levels. Both levels of muscle tension in the legs attenuated the LBNP-induced decrease in blood pressure (P less than 0.05). The effect of the 5% maximal voluntary contraction tension level appeared to be due to a compressive effect on the vascular tree, because similar levels of tension in the forearm had minimal effect on the blood pressure response to LBNP. In addition to a compressive effect, the 10% maximal voluntary contraction tension level appeared to induce a reflex stimulation of the heart as evidenced by an augmented heart rate response to LBNP and an increase in cardiac output. The muscle tension appeared to induce a mechanical compression of the vascular tree which was accompanied by somatopressor reflex responses, resulting in a maintenance of blood pressure that was primarily mediated by a maintained cardiac output.
Regional vascular responses to gradual reductions in right atrial pressure and aortic pressure were investigated in 9 men. In each study, lower body negative pressure was applied in a ramp of -1 mm Hg/min for 40-50 minutes. During the range from control to -20 mm Hg, right atrial pressure (4 studies) fell from 4.2 mm Hg to -0.6 mm Hg; heart rate was slightly reduced (2 beats/min), and aortic mean pressure and pulse pressure (6 studies) were unchanged. The maximal rate of rise of aortic pressure showed no consistent trends. Forearm blood flow (30 studies) fell with the onset of lower body negative pressure and reached 67% of the control value by -20 mm Hg. Splanchnic blood flow (14 studies) was significantly reduced by -7 mm Hg and fell to 89% of control by -20 mm Hg. During the range from -20 to -50 mm Hg, right atrial pressure continued to fall. Aortic mean pressure fell slightly or was unchanged in four subjects and fell dramatically at -35 mm Hg in 2 subjects. Aortic pulse pressure began to fall at about -20 mm Hg and fell linearly thereafter. Heart rate paralleled aortic pulse pressure (r=-0.86 to -0.93). Forearm blood flow fell to 55% and splanchnic blood flow fell to 65% of control at -50 mm Hg. Thus, significant vasoconstriction occurred without measurable change in arterial blood pressure. It is concluded that low pressure baroreceptors, presumably in the cardiopulmonary region, initiate splanchnic and forearm vasoconstriction with more pronounced vasoconstriction occurring in the forearm.
Brief, maximal isometric exercise of six seconds' duration, repeated three times daily for five to eight weeks may be associated with lowering of the blood pressure in hypertensive patients. In 8 subjects with hypertension there was a decrease of 16-42 mm Hg in systolic pressure and 2-24 mm in diastolic pressure. In 5 subjects receiving a constant dosage of hypotensive drugs, there was a decrease of 4-28 mm in systolic pressure and 2-14 mm in diastolic pressure. In 2 subjects previously treated with hypotensive drugs in whom isometric exercise was substituted for the drugs, normal blood pressure was maintained for eleven months.
1. 1. Orthostatic tolerance of normal subjects is markedly diminished by the use of intravascular instrumentation such as venous catheters and intraarterial needles. 2. 2. Psychic stimulation due to discomfort or unconscious fear and anxiety associated with such instrumentation may interfere with compensatory reflexes activated by the upright posture and mediated through the central nervous system. 3. 3. Individual reactions to orthostasis vary greatly. Within three minutes following upright tilting, late fainters who were then asymptomatic showed the same decrease in cardiac index and stroke volume as nonfainters. With the onset of symptoms of presyncope, the cardiac index further decreased to 39 per cent of baseline, but nonfainters manifested only a 19 per cent decrease after 20 min. of orthostasis. 4. 4. Recumbent systolic pressure was found to be significantly lower in early fainters than in nonfainters. After three minutes of orthostasis, asymptomatic late fainters had a significantly lower systolic and narrower pulse pressure than nonfainters at the same time. This finding suggests an incomplete compensatory response to the orthostatic stress. 5. 5. Effective cerebral arterial pressure was maintained in nonfainters, but markedly decreased in fainters prior to syncope. 6. 6. The 19 per cent decrease in cardiac index found after 20 min. of orthostasis is associated with a 36 per cent increase in peripheral resistance and a 7 per cent increase in mean arterial pressure. A similar decrease in cardiac index in the recumbent position was associated with only a 14 per cent increase in peripheral resistance and a 5 per cent decrease in mean arterial pressure. This discrepancy in response to central cardiac changes is probably related to the relative effects of the upright posture on cerebral arterial pressure or peripheral vascular receptors.
Subtolerance and presyncopal lower body negative pressure (LBNP) has been used extensively to investigate the effect of various forms of exercise training on central hypovolemic tolerance. However, there are no population data concerning LBNP tolerance, and the validity of common LBNP tolerance indices has not been investigated. LBNP tolerance data from 86 males and 33 females were analyzed. All LBNP exposures were terminated with the onset of presyncopal signs and/or symptoms. LBNP tolerance was quantified using duration of exposure (DNP), maximal negative pressure tolerated (MNP, cumulative stress index (CSI), and the LBNP tolerance index (LTI). Average (+/- SD) LBNP tolerance was 22.12 +/- 5.01 min (DNP), -77 +/- 16 mm Hg (MNP), 975 +/- 402 mm Hg.min-1 (CSI), or 222 +/- 50 mm Hg.min-1 (LTI). All cardiovascular parameters exhibited the same responses as have been documented in the literature. While DNP, MNP, and LTI were normally distributed, CSI in this population was not normally distributed. Age, weight, height, gender, and VO2peak were not associated with LBNP tolerance. Compared to this population, it appears that the subjects that have participated in previous LBNP tolerance studies have had abnormally high LBNP tolerances and that the LTI is the most valid index of LBNP tolerance. Furthermore, in this population LBNP tolerance could not be predicted from physical characteristics.
1. Studies were carried out on 43 otherwise healthy patients referred for investigation for attacks of syncope of unknown cause and on six healthy volunteers.
2. Plasma volume was determined by Evans Blue dye dilution and blood volume was estimated using haematocrit. Carotid baroreceptor sensitivity was determined from the changes in pulse interval in response to subatmospheric pressures applied to the neck overlying the carotid sinuses, and orthostatic tolerance was assessed as the time to presyncope in a test of head-up tilt, followed by the addition of graded lower body suction.
3. Eight patients and one volunteer fainted during head-up tilt alone, 23 patients and two volunteers fainted during tilt with lower body suction at −20 mmHg and 12 patients and three volunteers either fainted during suction at −40 mmHg or tolerated the entire procedure.
4. Although plasma and blood volumes were higher in males than females, the values normalized for either body weight or for calculated lean body mass were not different between male and female patients and asymptomatic volunteers. The subjects showing the greatest resistance to syncope were found to have significantly larger plasma and blood volumes (P < 0.0001) and significantly smaller baroreceptor sensitivities (P < 0.0002) than those who fainted earlier.
5. There was a highly significant positive correlation in all subjects between orthostatic tolerance (time to onset of syncope) and plasma and blood volumes (r = 0.60, P < 0.0001; r = 0.53, P < 0.0002), and highly significant negative correlations between time to syncope and baroreceptor sensitivity (r = −0.61, P < 0.0001) and between baroreceptor sensitivity and plasma and blood volumes (r = −0.54, P < 0.0001; r = −0.31, P < 0.03).
6. These results show that tolerance to orthostatic stress is favoured by large plasma and blood volumes and a low sensitivity of the carotid baroreceptor—heart rate reflex.
OBJECTIVE: To determine the accuracy of the TM-2430 blood pressure monitor, recently developed by the A&D company. DESIGN: Evaluation was performed using the 1990 and 1993 British Hypertension Society (BHS) protocols. Monitor's performance was assessed in relation to subjects' age, sex, level of blood pressure, and degree of adiposity. METHODS: Three TM-2430 recorders were assessed according to the various phases of the protocols. Simultaneous, same-arm readings were taken for the main validation test. Outcome was classified according to the criteria from the 1990 BHS recommendations, which are based on the cumulative percentage of readings differing from the mercury sphygmomanometer standard by 5, 10, and 15 mmHg or less, and using the criteria of the Association for the Advancement of Medical Instrumentation protocol, which considers a device accurate when the mean device-observer difference is within 5 mmHg and the related SD < 8 mmHg. RESULTS: During in-use assessment 2.3% of total measurements (N = 3744) were rejected automatically by the machine and another 5.5% werre discarded after visual inspection. The main validation test was performed with 98 subjects for a total of 595 blood pressure measurements. On the basis of the percentages of measurements differing from the mercury sphygmomanometer standard by </= 5, </= 10, and </= 15 mmHg, the TM-2430 device was graded A both for systolic blood pressure and for diastolic blood pressure. Differences between mean blood pressures as measured by device and observer were 2.2 +/- 3.9 mmHg for systolic blood pressure and 0.7 +/- 4.4 mmHg for diastolic blood pressure. The device's performance did not vary according to subjects' age, sex, and body mass, and was slightly better for subjects with high blood pressures and lean arms. CONCLUSION: These data show that the A&D TM-2430 monitor satisfies the recommended BHS and Association for Advancement of Medical Instrumentation accuracy levels for both systolic and diastolic blood pressures.
The purpose of this study was to determine whether isometric handgrip (IHG) training reduces arterial pressure and whether reductions in muscle sympathetic nerve activity (MSNA) mediate this drop in arterial pressure. Normotensive subjects were assigned to training (n = 9), sham training (n = 7), or control (n = 8) groups. The training protocol consisted of four 3-min bouts of IHG exercise at 30% of maximal voluntary contraction (MVC) separated by 5-min rest periods. Training was performed four times per week for 5 wk. Subjects' resting arterial pressure and heart rate were measured three times on 3 consecutive days before and after training, with resting MSNA (peroneal nerve) recorded on the third day. Additionally, subjects performed IHG exercise at 30% of MVC to fatigue followed by muscle ischemia. In the trained group, resting diastolic (67 +/- 1 to 62 +/- 1 mmHg) and mean arterial pressure (86 +/- 1 to 82 +/- 1 mmHg) significantly decreased, whereas systolic arterial pressure (116 +/- 3 to 113 +/- 2 mmHg), heart rate (67 +/- 4 to 66 +/- 4 beats/min), and MSNA (14 +/- 2 to 15 +/- 2 bursts/min) did not significantly change following training. MSNA and cardiovascular responses to exercise and postexercise muscle ischemia were unchanged by training. There were no significant changes in any variables for the sham training and control groups. The results indicate that IHG training is an effective nonpharmacological intervention in lowering arterial pressure.
The cardiovascular responses to upright tilting and lower body negative pressure in man
- Y. M. H. Al-Shamma
- R. Hainsworth
- Y. M. H. Al-Shamma
- R. Hainsworth
Human Baroreflexes in Health and Disease. Monographs of The Physiological Society No
- D L Eckberg
- P Sleight
A study of factors affecting tolerance of gravitational stress simulated by lower body negative pressure. Specialized Physiological Studies in Support of Manned Space Flight (Contract NAS9-14472)
- U C Luft
- L G Myhre
- J A Loeppky
- M D Venters
Quantification of tolerance to lower body negative pressure in a healthy population
- J T Lightfoot
- K M Tsintgaris
The cardiovascular responses to upright tilting and lower body negative pressure in man
- Al-Shamma