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The study aimed to determine the effects of two differing amino acid beverage interventions on biomarkers of intestinal epithelial integrity and systemic inflammation in response to an exertional-heat stress challenge. One week after the initial assessment, participants ( n = 20) were randomly allocated to complete two exertional-heat stress trials...
Context in source publication
Context 1
... schematic description of the heat exertion amino acid technology study and associated experimental procedures are depicted in Fig- ure 1. Heat exertion amino acid technology was conducted in accordance with best practice guidelines for exercise gastroenterology as described in Costa et al. (2022). ...
Citations
... 12 Whereby, in response to EHS and compared with a water control, two amino acid beverage blends [i.e., 4.5 g/L (valine, aspartic acid, serine, threonine, and tyrosine) and 6.4 g/L (aspartic acid, serine, valine, isoleucine, threonine, and tyrosine)] presented attenuating effects on intestinal epithelial cell injury, luminal pathogenic translocation, and systemic inflammatory responses, without exacerbating gastrointestinal symptoms commonly associated with the exercise-induced gastrointestinal syndrome (EIGS) pathophysiological pathway. 12,22 A gap in the literature remains in exploring the impact of bacteraemia in response to EHS and nutritional strategies that may mitigate these effects. Therefore, the current study aimed to explore the extent to which EHS promotes exercise-associated bacteraemia, and to explore whether there are any mitigating effect/s of an amino acid beverage intervention on exercise-associated bacteraemia. ...
... 10,11 Several nutrition interventions (e.g., macronutrients and derivatives) prior to and during EHS that aim to minimise intestinal injury and permeability have previously been studied. 12,13 J o u r n a l P r e -p r o o f Journal Pre-proof achieved was confirmed from the V̇O-work rate relationship (9.9 (1.2) km/h) and was utilised as the running speed for the exercise trials. ...
... In accordance with our hypothesis, it is increased permeability). 2,3,12,36,37 Moreover, it is unlikely that such translocation is due to tightjunction leak pathways (i.e., exercise-associated intestinal epithelial hyperpermeability), considering the limiting size (e.g., <12.5 nm) and stringently regulated inter-cellular tightjunction space. 35 Tight-junction paracellular translocation may allow for bacterial endotoxin (e.g., LPS) to leak into systemic circulation due to small size dimension, as described in previous exercise studies; but does not allow for bacteria translocation that presents greater matter size. ...
... It is now well established that carbohydrate feeding before and frequently during exertional and exertional-heat stress models ameliorates injury to the intestinal epithelium by maintaining portal vein blood flow (Rehrer et al. 2005), albeit via plasma I-FABP measurements (Lambert et al. 2007;Snipe et al. 2017;Costa et al. 2017a;Miall et al. 2018;Jonvik et al. 2019). The current study provided carbohydrates (30 g h −1 ) during the first 120 min and a lactulose solution at 150 min, which likely explains the lower plasma I-FABP values compared to similar exercise models when no carbohydrates are provided during exercise and reporting substantially higher I-FABP values (Snipe et al. 2017(Snipe et al. , 2018bCosta et al. 2023). However, it is also possible that the modest plasma I-FABP concentration increases pre-to post exercise, in both HC-HFOD and HC-LFOD, are due to the 48 h high carbohydrate (HC-HFOD 9.1 ± 1.0 g kg BM −1 day −1 and HC-LFOD 9.8 ± 1.3 g kg BM −1 day −1 ) intake before the exercise protocol. ...
This study investigated the effects of a high carbohydrate diet, with varied fermentable oligo- di- mono- saccharide and polyol (FODMAP) content, before endurance exercise on gastrointestinal integrity, motility, and symptoms; and subsequent exercise performance. Twelve endurance athletes were provided with a 48-h high carbohydrate (mean±SD: 12.1±1.8g·kgˑday-1) diet on two separate occasions, composed of high (54.8±10.5g·day-1) and low FODMAP (3.0±0.2g·day-1) content. Thereafter, participants completed a 2-h steady-state running exercise at 60% of VO2max (22.9±1.2°C, 46.4±7.9% RH), followed by a 1-h distance performance test. Pre-exercise and every 20-min during steady-state exercise, 100mL maltodextrin (10% w/v) solution was consumed. A 150mL lactulose (20g) solution was consumed 30-min into the distance performance test to determine orocecal transit time (OCTT) during exercise. Blood was collected pre- and post-exercise to determine gastrointestinal integrity biomarkers (i.e., I-FABP, sCD14, and CRP). Breath hydrogen (H2) and gastrointestinal symptoms (GIS) were determined pre-exercise, every 15-min during, and throughout recovery. No differences in gastrointestinal integrity biomarkers, OCTT, or distance completed were observed between trials. Pre-exercise total-GIS (1.3±2.9 vs. 4.3±4.4), gut discomfort (9.9±8.1 vs. 15.8±9.0) and upper-GIS (2.8±2.6 vs. 5.7±4.8) during exercise were less severe on HC-LFOD vs. HC-HFOD (p<0.05). Gut discomfort (3.4±4.4 vs. 0.2±0.6) and total-GIS (4.9±6.8 vs. 0.2±0.6) were higher during recovery on HC-LFOD vs. HC-HFOD (p<0.05). The FODMAP content of a 48-h high carbohydrate diet does not impact gastrointestinal integrity or motility in response to endurance exercise. However, a high FODMAP content exacerbates GIS before and during exercise, but this does not impact performance outcomes.
... Data from four experimental trials using the same EHS model were extracted for data analysis [5][6][7]32]. Data collection for each experimental trial took place between 2014 to 2015 [6], 2015 to 2016 [5], 2018 [7] and 2021 to 2022 [32]. Sixteen masters (MASTERS) and twenty-one younger adult (YOUNG) recreationally trained, non-acclimatized, endurance athletes volunteered to participate in the respective EHS studies (▶table 1). ...
... Data from four experimental trials using the same EHS model were extracted for data analysis [5][6][7]32]. Data collection for each experimental trial took place between 2014 to 2015 [6], 2015 to 2016 [5], 2018 [7] and 2021 to 2022 [32]. Sixteen masters (MASTERS) and twenty-one younger adult (YOUNG) recreationally trained, non-acclimatized, endurance athletes volunteered to participate in the respective EHS studies (▶table 1). ...
... One week prior to the experimental trial, participants visited the laboratory to have their height, body mass and body fat measured (Seca 515 MBCA, Seca Group, Hamburg, Germany). Maximal oxygen uptake (V O 2max ; Vyntus, Vyaire Medical, Mettawa, Illinois, USA) was estimated by means of a continuous incremental exercise test to volitional exhaustion on a motorized treadmill (Pulsar, h/p/cosmos, Munich, Germany) as previously presented in the original study procedures [5][6][7]32]. To determine running speed for the experimental trials, the treadmill speed at approximately 60 % V̇O 2max and 1 % gradient was determined and verified from the V̇O 2work rate relationship (▶table 1). ...
This meta-data exploration aimed to determine the impact of exertional-heat stress (EHS) on gastrointestinal status of masters age and young adult endurance athletes. Sixteen MASTERS (mean: 44y) and twenty-one YOUNG (26y) recreational endurance athletes completed 2 h of running at 60% ˙V O2max in 35˚C ambient conditions. Blood samples were collected pre-, immediately and 1 h post-EHS, and analyzed for markers of exercise-induced gastrointestinal syndrome (EIGS). Thermo-physiological measures and gastrointestinal symptoms (GIS) were recorded every 10–20 min during EHS. Peak Δ pre- to post-EHS did not substantially differ (p>0.05) between MASTERS and YOUNG for intestinal epithelial injury [I-FABP: 1652pg/ml vs. 1524pg/ml, respectively], bacterial endotoxic translocation [sCD14: -0.09µg/mL vs. 0.84µg/mL, respectively], lipopolysaccharide-binding protein [LBP: 0.26µg/mL vs. 1.76µg/mL, respectively], and systemic inflammatory response profile (SIR-Profile: 92.0arb.unit vs. 154arb.unit, respectively). A significantly higher peak Δ pre- to post-EHS in endogenous endotoxin anti-body IgM (p=0.042), and pro-inflammatory cytokine IL-1β (p=0.038), was observed in YOUNG compared to MASTERS. No difference was observed between incidence (81% and 80%, respectively) and severity (summative accumulation: 21 and 30, respectively) of reported GIS during EHS between MASTERS and YOUNG. Pathophysiology of EIGS in response to EHS does not substantially differ with age progression, since masters and younger adult endurance athletes responded comparably.
... Metadata from 12 experimental trials, within 9 previously published research studies, that utilized an exertional or exertional-heat stress exercise model (i.e. 2 h of running exercise in an ambient-controlled environment) were used for this exploratory data analyses [13,[15][16][17][18][19][20]28,37]. One hundred and thirty-two trials were included from endurance-trained individuals [mean ± SD (male n = 97, female n = 35): age 32.1 ± 7.7 years, nude body mass 70.8 ± 10.8 kg, height 1.70 ± 0.28 m, % body fat mass 15.5 ± 5.8, VO 2max 57.7 ± 7.9 mL·kgBM −1 ·min −1 , training load 457 ± 245 min·week −1 (i.e. ...
... Each participant completed a 2 h exercise protocol, consisting of running at steady state at 60% VO 2max [13,[18][19][20]28,37], or a high-intensity interval ranging between ~55% to 80% VO 2max [15][16][17], in ambient temperatures (T amb ) ranging from 21.2°C to 37.5°C and 20.1% to 50.0% relative humidity (RH), with a fan air speed at fan airspeed ~10.6 km·h −1 . Core body temperature was determined through rectal temperature (T re ) and gastrointestinal symptoms were recorded every 10-15 min during the exercise trial. ...
... The plasma concentrations of systemic inflammatory cytokines TNFα, IL-1β, IL-6, IL-8, IL-10 and IL-1ra (HCYTOMAG-28SK; MilliporeSigma, Darmstadt, Germany) were assessed via multiplex system. Analytical procedures and assay coefficient of variation are reported within the original research publication [13,[15][16][17][18][19][20]28,37]. Considering the large intra-and inter-individual variation in inflammatory cytokine responses previously observed, the peak Δ pre-to post-exercise for pro-inflammatory (IL-1β and TNF-α), response/modulatory (IL-6 and IL-8) and antiinflammatory (IL-10 and IL-1ra) cytokines were combined to establish an exercise-associated systemic inflammatory response profile (SIR-Profile) for comparative purposes, as previously described [21]. ...
Purpose
Utilising metadata from existing exertional and exertional-heat stress studies, the study aimed to determine if the exercise-associated increase in core body temperature can predict the change in exercise-induced gastrointestinal syndrome (EIGS) biomarkers and exercise-associated gastrointestinal symptoms (Ex-GIS).
Method
Endurance-trained individuals completed 2h of running exercise in temperate (21.2-30.0°C) to hot (35.0-37.2°C) ambient conditions (n=132 trials). Blood samples were collected pre- and post-exercise to determine the change in gastrointestinal integrity biomarkers and systemic inflammatory cytokines. Physiological and thermoregulatory strain variables were assessed every 10-15min during exercise. The strength of the linear relationship between maximal (M-Tre) and change (Δ Tre) in rectal temperature and EIGS variables was determined via Spearman’s rank correlation coefficients. While the strength of prediction was determined via simple and multiple linear regression analyses dependent on screened EIGS and Ex-GIS confounding factors.
Results
Significant positive correlations between Tre maximum (M-Tre) and change (Δ Tre) with I-FABP (rs=0.434, p<0.001; and rs=0.305, p<0.001; respectively), sCD14 (rs=0.358, p<0.001; and rs=0.362, p<0.001), systemic inflammatory response profile (SIR-Profile) (p<0.001), and total Ex-GIS (p< 0.05) were observed. M-Tre and Δ Tre significantly predicted (adjusted R²) magnitude of change in I-FABP (R²(2,123)=0.164, p<0.001; and R²(2,119)=0.058, p=0.011; respectively), sCD14 (R²(2,81)=0.249, p<0.001; and R²(2,77)=0.214, p<0.001), SIR-Profile (p<0.001) and total Ex-GIS (p<0.05).
Conclusion
Strong to weak correlations were observed between M-Tre and Δ Tre with plasma concentrations of I-FABP, sCD14, SIR-Profile, and Ex-GIS in response to exercise. M-Tre and Δ Tre can predict the magnitude of these EIGS variables and Ex-GIS in response to exercise.
Hypohydration can impair aerobic performance and deteriorate cognitive function during exercise. To minimize hypohydration, athletes are recommended to commence exercise at least euhydrated, ingest fluids containing sodium during long-duration and/or high-intensity exercise to prevent body mass loss over 2% and maintain elevated plasma osmolality, and rapidly restore and retain fluid and electrolyte homeostasis before a second exercise session. To achieve these goals, the compositions of the fluids consumed are key; however, it remains unclear what can be considered an optimal formulation for a hydration beverage in different settings. While carbohydrate–electrolyte solutions such as sports drinks have been extensively explored as a source of carbohydrates to meet fuel demands during intense and long-duration exercise, these formulas might not be ideal in situations where fluid and electrolyte balance is impaired, such as practicing exercise in the heat. Alternately, hypotonic compositions consisting of moderate to high levels of electrolytes (i.e., ≥45 mmol/L), mainly sodium, combined with low amounts of carbohydrates (i.e., <6%) might be useful to accelerate intestinal water absorption, maintain plasma volume and osmolality during exercise, and improve fluid retention during recovery. Future studies should compare hypotonic formulas and sports drinks in different exercise settings, evaluating different levels of sodium and/or other electrolytes, blends of carbohydrates, and novel ingredients for addressing hydration and rehydration before, during, and after exercise.
