How Much Sleep Does an Elite Athlete Need?

Abstract

Purpose:
Anecdotal reports indicate that many elite athletes are dissatisfied with their sleep, but little is known about their actual sleep requirements. Therefore, the aim of this study was to compare the self-assessed sleep need of elite athletes with an objective measure of their habitual sleep duration.

Methods:
Participants were 175 elite athletes (n = 30 females), age 22.2 (3.8) years (mean [SD]) from 12 individual and team sports. The athletes answered the question "how many hours of sleep do you need to feel rested?" and they kept a self-report sleep diary and wore a wrist activity monitor for ∼12 nights during a normal phase of training. For each athlete, a sleep deficit index was calculated by subtracting their average sleep duration from their self-assessed sleep need.

Results:
The athletes needed 8.3 (0.9) hours of sleep to feel rested, their average sleep duration was 6.7 (0.8) hours, and they had a sleep deficit index of 96.0 (60.6) minutes. Only 3% of athletes obtained enough sleep to satisfy their self-assessed sleep need, and 71% of athletes fell short by an hour or more. Specifically, habitual sleep duration was shorter in athletes from individual sports than in athletes from team sports (F1,173 = 13.1, P < .001; d = 0.6, medium), despite their similar sleep need (F1,173 = 1.40, P = .24; d = 0.2, small).

Conclusions:
The majority of elite athletes obtain substantially less than their self-assessed sleep need. This is a critical finding, given that insufficient sleep may compromise an athlete's capacity to train effectively and/or compete optimally.

Full text

How Much Sleep Does an Elite Athlete Need?
Charli Sargent, Michele Lastella, Shona L. Halson, and Gregory D. Roach
Purpose: Anecdotal reports indicate that many elite athletes are dissatisfied with their sleep, but little is known about their actual
sleep requirements. Therefore, the aim of this study was to compare the self-assessed sleep need of elite athletes with an objective
measure of their habitual sleep duration. Methods: Participants were 175 elite athletes (n = 30 females), age 22.2 (3.8) years
(mean [SD]) from 12 individual and team sports. The athletes answered the question “how many hours of sleep do you need to
feel rested?”and they kept a self-report sleep diary and wore a wrist activity monitor for ∼12 nights during a normal phase of
training. For each athlete, a sleep deficit index was calculated by subtracting their average sleep duration from their self-assessed
sleep need. Results: The athletes needed 8.3 (0.9) hours of sleep to feel rested, their average sleep duration was 6.7 (0.8) hours,
and they had a sleep deficit index of 96.0 (60.6) minutes. Only 3% of athletes obtained enough sleep to satisfy their self-assessed
sleep need, and 71% of athletes fell short by an hour or more. Specifically, habitual sleep duration was shorter in athletes from
individual sports than in athletes from team sports (F
1,173
= 13.1, P<.001; d= 0.6, medium), despite their similar sleep need
(F
1,173
= 1.40, P= .24; d= 0.2, small). Conclusions: The majority of elite athletes obtain substantially less than their self-
assessed sleep need. This is a critical finding, given that insufficient sleep may compromise an athlete’s capacity to train
effectively and/or compete optimally.
Keywords:sleep duration, sleep need, sleep deficit, recovery
The true function of sleep is not yet fully understood, but it
plays an important role in energy conservation,
1
nervous system
recuperation,
2
host-defense mechanisms,
3
and restoration of opti-
mal performance
4
—all of which are critical for elite athletes. The
amount of sleep required to maintain these functions is a natural
and relevant question, and many athletes and coaches seek guid-
ance regarding targets for sufficient sleep duration.
The appropriate sleep duration recommended by the US
National Sleep Foundation is 7 to 9 hours for young adults (18–
25 y) and 7 to 8 hours for other adults (26–64 y).
5
These recom-
mendations were developed by an 18-member expert panel and are
based on a systematic review of medical and scientific research
regarding the consequences of either too little, or too much, sleep for
health and performance. When compared against these general
benchmarks, elite athletes typically obtain less sleep than is recom-
mended
6–11
or the minimum amount of sleep that is recom-
mended.
12–14
The National Sleep Foundation’s guidelines are useful for
identifying potential deficiencies in habitual sleep duration at a
broad level, but they are not sensitive to individual differences in
sleep need. In general, many aspects of mental performance are
impaired by sleep loss in a dose-dependent fashion—that is, the
less sleep obtained, the poorer the performance.
15,16
However,
there is considerable variability in the individual response to
sleep loss—some maintain good levels of performance, while
others perform poorly.
17
At present, we do not have a good
understanding of how much sleep an elite athlete needs, nor do
we know whether they obtain their required sleep need on a
habitual basis. It is possible that some athletes may require less
sleep than recommended by the National Sleep Foundation, while
others may require more.
The aims of the present study were to (1) identify the subjective
sleep need of elite athletes and compare it with an objective measure
of their habitual sleep duration; (2) examine the relationships
between habitual sleep onset, habitual sleep offset, and habitual
sleep duration; (3) compare sleep variables between individual and
team sports; and (4) compare sleep variables between sexes. We
hypothesize that objective habitual sleep duration in elite athletes
will be lower than their subjective sleep need.
Methods
Participants
A total of 175 elite athletes from 12 sports (Australian Rules
football, basketball, cricket, kayaking, mountain biking, race walk-
ing, road cycling, rugby union, soccer, swimming, track cycling, and
triathlon) gave informed consent to participate in the study (Table 1).
Athletes were volunteers from national teams of which the coaching
staff had expressed an interest in having the sleep of their athletes
monitored. Participants were excluded if they were training or
sleeping at altitude, if they were injured, if they reported a clinical
diagnosis of a sleep disorder, or if they had undertaken transmeridian
travel in the 2 weeks prior to data collection. According to the
National Sleep Foundation’s Guidelines,
5
11 athletes were catego-
rized as teenagers, 128 were classified as young adults, and 26 were
classified as adults. The study was approved by the Human Research
Ethics Committees of Central Queensland University and the
University of South Australia.
Procedures
Athletes’sleep/wake behavior was monitored for a minimum of 4
nights during a normal phase of training outside of competition
using self-report paper sleep diaries in conjunction with wrist
Sargent, Lastella, and Roach are with the Appleton Institute for Behavioural
Science, Central Queensland University, Adelaide, SA, Australia. Halson is with
the School of Behavioural and Health Sciences, Australian Catholic University,
Brisbane, QLD, Australia. Sargent (charli.sargent@cqu.edu.au) is corresponding
author.
1
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activity monitors. Each athlete wore an activity monitor on the
same wrist throughout the data collection period, except when
showering, swimming, or training. The sleep diaries were used to
record 2 pieces of information for each nighttime sleep: start date/
time and end date/time. Daytime naps were not recorded. Athletes
were instructed to complete their sleep diary each morning 30 min-
utes after waking. There was no experimental manipulation of the
athletes’training schedules or sleep/wake behaviors, and the
athletes were free to consume training supplements, caffeine, or
alcohol during the data collection period. Information regarding
medication use (including sleeping pills) was not collected. Prior to
the commencement of data collection, athletes completed a series
of questions presented in the front of the sleep diary to assess sleep
need, sleep satisfaction, and sleep quality. Data collected from
some of the athletes included in the present study have been
reported elsewhere.
6–9,18,19
Subjective and Objective Sleep Measures
A series of pen/paper questions were used to capture information
regarding athletes’perspectives of their sleep. These included:
1. Sleep need (in hours), assessed with the question “How many
hours of sleep do you need to feel rested?”;
2. Sleep satisfaction (in arbitrary units), assessed with the ques-
tion “How satisfied are you with the amount of sleep you get?”;
responses were rated using a 10-point scale, where 1 = very
dissatisfied and 10 = very satisfied;
3. Sleep quality (in arbitrary units), assessed with the question
“Overall, how would you rate the quality of your sleep?”;
responses were rated using a 6-point Likert scale, where
1 = very poor, 2 = poor, 3 = fair, 4 = good, 5 = very good,
and 6 = excellent.
Due to availability, 2 different models of activity monitor—
produced by a sole manufacturer—were used in this study
(Actiwatch-64 and Actical Z-series; Philips Respironics, Bend,
OR). The monitors were configured to sum and store data in
1-minute epochs based on activity counts from a piezoelectric
accelerometer with a sensitivity of 0.05 g and a sampling rate of
32 Hz. Data from the sleep diary and activity monitor were used to
determine when participants were awake and when they were
asleep. Essentially, all time was scored as wake unless: (1) the
sleep diary indicated that the athlete was lying down attempting to
sleep and (2) the activity counts from the monitor were sufficiently
low to indicate that the athlete was immobile.
20
When these 2
conditions were satisfied simultaneously, time was scored as sleep.
In this study, sensitivity was set at medium, which corresponds to a
threshold activity count of 40. (Please note: Sensitivity can be set at
“low”for elite athletes instead of medium, but this may only be
suitable when using the Actiwatch-64.) This scoring process was
conducted using a Philips Respironics’Actiwatch algorithm. Vali-
dation studies comparing wrist activity monitors with polysomno-
graphy report high levels of agreement in healthy adults (88%)
21
and well-trained athletes (81%–90%).
22
For each athlete, the following variables were derived for each
sleep period:
1. Sleep onset (in hours:minutes): the time at which an athlete
first fell asleep after going to bed;
2. Sleep offset (in hours:minutes): the time at which an athlete
last woke before getting up;
3. Sleep duration (in hours): the amount of sleep obtained during
a sleep period, that is, between sleep onset and sleep offset.
The athletes’sleep was monitored for an average of 12 (4)
(mean [SD]) nights. Habitual values for the 3 objective sleep
variables were calculated by averaging sleep onset, sleep offset,
and sleep duration using the number of nights of data available for
each athlete. In addition, a “sleep deficit index”was calculated for
each athlete by subtracting “habitual sleep duration”(objective
measure) from “sleep need”(subjective measure).
Table 1 Participant Characteristics
Participants n Age, y BMI, kg/m
2
Total 175 22.2 (3.8) 24.3 (3.7)
Men 145 22.4 (3.7) 24.8 (3.8)
Women 30 21.1 (4.5) 21.8 (2.2)
Sport
Alpine skiing 1 22.0 (NA) NA (NA)
Australian Rules football 43 22.3 (3.3) 24.3 (3.9)
Basketball 11 17.3 (0.9) 23.2 (1.4)
Cricket 17 23.9 (3.8) 24.4 (1.1)
Diving 1 18.0 (NA) 23.7 (NA)
Kayaking 2 24.0 (0.0) 26.5 (2.5)
Mountain biking 7 25.7 (4.7) 20.9 (1.0)
Race walking 4 22.5 (4.1) 20.3 (1.4)
Road cycling 9 19.2 (1.2) 22.3 (1.4)
Rugby union 29 24.6 (3.5) 29.8 (2.9)
Soccer 20 20.3 (3.5) 23.8 (1.7)
Swimming 8 22.6 (4.9) 22.8 (2.0)
Track cycling 6 23.3 (2.0) 26.3 (1.7)
Triathlon 17 21.2 (2.8) 20.4 (1.5)
Abbreviations: BMI, body mass index; NA, not applicable. Note: Data are presented as mean (SD).
2Sargent et al
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Statistical Analyses
Descriptive analyses of athletes’subjective and objective sleep
variables were conducted. All variables were normally distributed
according to the Kolmogorov–Smirnov normality test.
The aims of the study were addressed by conducting a series of
linear mixed effects models using the variance components covari-
ance structure and restricted maximum likelihood estimation. To
examine the difference between sleep need and habitual sleep duration
for the entire sample, “sport”was entered as a random effect into the
model and “type of measurement”(ie, sleep need or habitual sleep)
was entered as a fixed effect. Separate models were then used to
examine the difference between habitual sleep duration and sleep
need in 9 of the 12 sports, with “type of measurement”entered as a
fixed effect. (Please note: Alpine skiing [n = 1], diving [n = 1], and
kayaking [n = 2] were not included in the sport-specific analyses.)
Two linear mixed effects models were used to examine the
impact of habitual sleep onset time and habitual sleep offset time on
habitual sleep duration. Habitual sleep duration was binned as a
function of habitual sleep onset time (9 ×30-min bins) and habitual
sleep offset time (8 ×30-min bins). In each model, “bin”was
entered as a fixed effect.
Three linear mixed effects models were used to examine
differences in the 7 sleep variables (3 ×subjective, 3 ×objective,
1×sleep deficit index) between individual and team sports, between
all sports, and between the sexes. In each of the respective models,
“sport type,”“sport,”and “sex”were entered as a single fixed effect.
Where appropriate, main effects were examined using pairwise
comparisons with a Bonferroni adjustment. Within- and between-
group effect sizes were calculated using Cohen d. Effect sizes were
interpreted as follows: 0.2 = small effect; 0.5 = medium effect, and
0.8 = large effect. All statistical analyses were performed using
SPSS (version 26; IBM Corp, Armonk, NY). Results are reported
as mean and SD and were considered significant at P<.05.
Results
Habitual Sleep Duration, Sleep Need, and Sleep
Deficit Index
The participants had a habitual sleep duration of 6.7 (0.8) hours,
which was significantly less than their self-assessed sleep need of
8.3 (0.9) hours (F
1,5.1
= 211.03, P<.001; d= 1.9, large), resulting
in a sleep deficit index of 96.0 (60.6) minutes (Table 2). Habitual
sleep duration was significantly less than self-assessed sleep need
for all sports (Figure 1).
The US National Sleep Foundation recommends that teenagers
aged 14–17 years obtain 8 to 10 hours of sleep each night and young
adults/adults aged 18–64 years obtain 7 to 9 hours of sleep each night.
In this sample, 3%, 88%, and 9% of participants had a self-assessed
sleep need that was below, within, and above their age-specific range,
respectively (Figure 2A and 2B). Furthermore, 63%, 37%, and 0% of
participants had a habitual sleep duration that was below, within, and
above their age-specific range, respectively (Figure 2C and 2D). Only
3% of participants habitually obtained a sufficient amount of sleep to
satisfy their self-assessed sleep need, and 71% of participants fell short
by an hour or more (Figure 2E and 2F).
Habitual Sleep Onset and Habitual Sleep Offset
On average, participants had habitual sleep onset and habitual sleep
offset times at 23:24 (00:42) and 07:18 (00:48) hours, respectively
(Table 2; Figures 3A and 4A). Habitual sleep duration was signifi-
cantly affected by both habitual sleep onset time (F
8,165
=5.1,
P<.001; d=0.9–2.0, large) and habitual sleep offset time (F
9,165
=
6.7, P<.001; d=1.0–3.2, large); earlier onset times and later offset
times both tended to result in greater habitual sleep duration
(Figures 3B and 4B).
Sleep Satisfaction and Sleep Quality
Participants rated their sleep quality as 3.9 (0.9) on a Likert scale
from 1 (very poor) to 6 (excellent) (Table 2). Similarly, participants
rated their sleep satisfaction as 6.8 (1.6) on an arbitrary scale from 1
(very dissatisfied) to 10 (very satisfied) (Table 2).
Sport-Based Comparisons
There was a main effect of sport type (ie, individual vs team sport)
on habitual sleep onset time, habitual sleep offset time, and habitual
sleep duration (Figure 5A–5C). Habitual sleep onset and offset
times were earlier in athletes from individual sport than athletes
from team sports, but habitual sleep duration was shorter in athletes
from individual sports than athletes from team sports. There was no
main effect of sport type on sleep need (F
1,173
= 1.40, P= .24;
d= 0.2, small), sleep satisfaction (F
1,171
= 0.15, P= .70; d= 0.1,
small), sleep quality (F
1,171
= 0.09, P= .76; d= 0.1, small), or sleep
deficit index (F
1,173
= 2.84, P= .09; d= 0.3, small).
There was a main effect of sport on habitual sleep onset time
(F
10,160
= 3.27, P=.001), habitual sleep offset time (F
10,160
=
11.05, P<.001), and habitual sleep duration (F
10,160
= 5.61,
P<.001) (Table 2). Habitual sleep onset was earliest in mountain
bikers and latest in rugby union players (Figure 6A), habitual sleep
offset was earliest in triathletes and latest in basketballers
(Figure 6B), and habitual sleep duration was shortest in triathletes
and longest in basketballers (Figure 6C). There was no main effect
of sport on sleep need (F
10,160
= 0.83, P= .60), sleep satisfaction
(F
10,158
= 0.86, P= .57), sleep quality (F
10,158
= 1.53, P= .13), or
sleep deficit index (F
10,160
= 1.44, P= .17).
Sex-Based Comparisons
There was a main effect of sex on habitual sleep onset time
(Figure 7A). Female athletes went to bed earlier than male athletes.
There was no main effect of sex on habitual sleep offset time or
habitual sleep duration (Figure 7B and 7C), nor was there an effect
on sleep need (F
1,173
= 0.17, P= .68; d= 0.1, small), sleep satis-
faction (F
1,171
= 0.06, P= .81; d= 0.1, small), sleep quality (F
1,171
=
0.22, P= .64; d= 0.1, small), or sleep deficit index (F
1,173
= 2.15,
P=.15; d= 0.3, small) (Table 2).
Discussion
The primary findings of this study are (1) athletes need 8.3 hours of
sleep to feel rested, (2) athletes typically obtain 6.7 hours of sleep,
(3) the most sleep is obtained by athletes who fall asleep between
22:00 and 22:30 hours (7.2 h) or wake up between 09:00 and
09:30 hours (7.6 h), (4) athletes involved in team sports (6.9 h)
obtain more sleep than athletes involved in individual sports
(6.4 h), and (5) female athletes have an earlier habitual sleep onset
time than male athletes. Importantly, only 3% of athletes obtain
enough sleep to satisfy their self-assessed sleep need, and 71% of
athletes fall short by an hour or more. Insufficient or inadequate
sleep, defined here as a failure to meet a required sleep need on a
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Table 2 Sleep Variables in Elite Athletes
Subjective variables Objective variables
Participants
Sleep
need, h
Sleep
satisfied,
units
Sleep
quality,
units
Nights
of data,
count
Habitual sleep
onset, h:min
Habitual sleep
offset, h:min
Habitual
sleep
duration, h
Sleep deficit
index, min
Total 8.3 (0.9) 6.8 (1.6) 3.9 (0.9) 12.0 (4.4) 23:24 (00:42) 07:18 (00:48) 6.7 (0.8) 96.0 (60.6)
Men 8.3 (0.9) 6.8 (1.6) 3.9 (0.9) 11.8 (4.2) 23:30 (00:42) 07:24 (00:48) 6.7 (0.7) 99.1 (60.6)
Women 8.3 (1.0) 6.9 (1.5) 4.0 (0.8) 12.9 (5.3) 23:12 (00:42) 07:06 (01:00) 6.8 (1.0) 81.3 (59.5)
Sport
Alpine skiing 6.0 (NA) 7.0 (NA) 3.0 (NA) 17.0 (NA) 01:18 (NA) 08:00 (NA) 5.6 (NA) 24.5 (NA)
Australian rules football 8.4 (0.8) 7.0 (1.7) 3.9 (1.0) 13.6 (0.9) 23:24 (00:33) 07:32 (00:31) 7.0 (0.7) 84.4 (42.1)
Basketball 8.5 (0.8) 6.9 (1.3) 4.3 (0.8) 12.5 (3.1) 23:24 (00:27) 07:54 (00:24) 7.5 (0.4) 64.9 (45.7)
Cricket 8.5 (1.0) 6.5 (1.1) 3.7 (0.8) 9.9 (3.8) 23:19 (00:44) 07:34 (00:36) 6.7 (0.6) 108.2 (77.5)
Diving 6.5 (NA) 3.0 (NA) 2.0 (NA) 13.0 (NA) 24:00 (NA) 06:30 (NA) 5.7 (NA) 45.6 (NA)
Kayaking 8.0 (0.7) 5.5 (2.1) 3.5 (0.7) 15.5 (0.7) 23:00 (00:30) 06:24 (00:36) 6.3 (0.3) 99.6 (61.7)
Mountain biking 8.5 (1.0) 7.0 (2.0) 3.8 (0.8) 12.0 (1.4) 22:49 (00:31) 07:11 (00:49) 7.3 (0.5) 74.6 (70.3)
Race walking 8.8 (1.0) 7.0 (1.4) 3.8 (1.0) 23.3 (5.4) 23:05 (00:28) 06:56 (00:48) 7.0 (0.5) 103.6 (81.1)
Road cycling 8.2 (0.4) 7.3 (1.9) 4.2 (0.7) 11.1 (4.1) 23:19 (00:40) 07:10 (00:18) 6.6 (0.9) 92.9 (53.5)
Rugby union 8.2 (0.8) 6.3 (1.7) 3.6 (0.8) 13.0 (2.7) 23:51 (00:42) 07:29 (00:48) 6.5 (0.7) 103.0 (63.3)
Soccer 8.4 (0.9) 7.4 (1.3) 4.1 (0.9) 5.4 (2.9) 23:39 (00:35) 07:45 (00:33) 7.0 (0.7) 86.6 (52.5)
Swimming 8.2 (1.6) 6.7 (1.5) 3.4 (0.9) 13.3 (1.5) 23:05 (01:00) 06:21 (01:07) 6.2 (0.5) 117.7 (114.6)
Track cycling 8.9 (0.6) 6.7 (2.1) 4.3 (0.8) 5.7 (0.8) 23:51 (01:51) 07:45 (01:16) 6.7 (1.0) 133.5 (52.5)
Triathlon 8.0 (0.7) 7.2 (1.4) 4.2 (0.7) 14.8 (4.9) 22:56 (00:28) 06:05 (00:20) 5.9 (0.8) 124.7 (51.2)
Abbreviation: NA = not applicable. Note: Data are presented as mean (SD). “Sleep need”is the amount of sleep, in hours, to feel rested; “sleep satisfied”is measured on a 10-point Likert scale, where 1 = “very dissatisfied”
and 10 = “very satisfied”;“sleep quality”is measured on a 6-point Likert scale, where 1 = “very poor”and 6 = “excellent”;“nights of data”is the number of nights on which sleep was assessed using an activity monitor;
“habitual sleep onset”is the mean clock time that an athlete first fell asleep after going to bed; “habitual sleep offset”is the mean clock time that an athlete last woke before getting up; “habitual sleep duration”is the mean
sleep duration calculated from the activity monitor record; and “sleep deficit index”is calculated as the difference between “sleep need”and “habitual sleep duration.”
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Figure 2 —Histograms representing the relative frequency and cumulative relative frequency of subjective sleep need (A and B), habitual sleep
duration (C and D), and sleep deficit index (E and F).
Figure 1 —Self-assessed sleep need compared with habitual sleep duration in athletes from 11 different sports. Mean values for each sport have been
offset for interpretability. Error bars represent SD.
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Figure 3 —Histogram representing the relative frequency of habitual sleep onset time (A) and bar charts (mean [SD]) with individual cases (open
circles) representing habitual sleep duration plotted as a function of mean habitual sleep onset time (B). The outcomes of the post hoc comparisons
between mean habitual sleep onset time bins and the corresponding effect sizes are presented in panel B. (Please note: The error bar on the final column in
panel B is obscured because the value is small.)
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Figure 4 —Histogram representing the relative frequency of habitual sleep offset time (A) and bar charts (mean [SD]), with individual cases (open
circles) representing habitual sleep duration plotted as a function of mean habitual sleep offset time (B). The outcomes of the post hoc comparisons
between mean habitual sleep offset time bins and the corresponding effect sizes are presented in panel B. (Please note: The standard deviation for the
penultimate column in panel B is equal to 0.)
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regular basis, could have important consequences for an elite
athlete, particularly in terms of their ability to train effectively
and/or compete optimally.
The average subjective sleep need reported by elite athletes in
this sample was 8.3 hours. Similar values have been reported by
healthy untrained adolescents (8.6 h; 17 [1] y) and adults (8.0 h; 36
[12] y).
23,24
Almost 80% of the current athletes reported needing
between 7 and 9 hours of sleep, suggesting that the US National
Sleep Foundation’s sleep duration recommendation of 7 to 9 hours
is reasonable for most athletes. However, sleep need varied
between individual athletes, with the lowest reported sleep need
of 5.5 hours (n = 1) and the highest reported sleep need of 11 hours
(n = 2). A general recommendation may be appropriate for the
majority of athletes, but the sleep need of some may substantially
differ from the prescribed target.
In the present study, a sleep deficit index was calculated by
subtracting athletes’habitual sleep duration from their subjective
sleep need (ie, 96.0 [60.6] min). A difference of 1 hour between
self-reported sleep need and sleep duration is typically considered
insufficient sleep.
25
In a large-scale epidemiological study with
healthy, untrained adults (n = 12,423; aged 33–60 y), the preva-
lence of insufficient sleep was 20%.
25
In the present study, the
prevalence of insufficient sleep was 71%. There are 2 main
alternatives that could explain a high prevalence of insufficient
sleep in a population—either sleep need is higher than normal or
the amount of sleep obtained is lower than normal. The latter
explanation seems the one most likely to apply to the athletes in this
study—the amount of sleep that they require is normal (8.3 h), but
the amount of sleep they habitually obtain (6.7 h) is not sufficient to
satisfy this requirement.
The average sleep duration observed in this cohort of elite
athletes was 6.7 hours; however, this value varied between sports.
In general, athletes from individual sports had earlier habitual sleep
onset and offset times but obtained less sleep than athletes from
team sports. Specifically, alpine skiing, diving, triathlon, swim-
ming, kayaking, rugby union, and road cycling habitually obtained
less sleep than the average, while athletes from basketball, moun-
tain bike, race walking, Australian Rules Football, soccer, track
cycling, and cricket habitually obtained more sleep than the
average. For some sports, the habitual sleep durations observed
in this study are similar to those reported previously (ie, Australian
Rules Football—7.0 h vs 6.9–7.1 h
14,26,27
; basketball—7.5 h vs
7.6 h
7,28
; soccer—7.0 h vs 7.2 h),
29
but, for other sports, the current
values are lower than those previously reported (ie, diving—5.7 h
vs 7.1 h
12
; rugby union—6.5 h vs 7.1 h).
30
It is not clear why the
habitual sleep duration differs between current and past studies for
some sports, but potential explanations include differences in the
physical demands of training,
31–33
the characteristics of the athletes
(eg, chronotype),
34
and/or the time of day that training sessions
occur.
8
It is plausible that longer habitual sleep durations could be
achieved by manipulating aspects of an athlete’s training schedule
(especially for individual sports) to ensure bedtimes and getup
times are optimized for sleep duration, but this is a question that is
yet to be empirically investigated.
The amount of sleep an individual obtains on a regular basis
does have implications for their ability to function effectively. A
number of studies have examined the impact of severe, acute
sleep loss on exercise and sports performance in athletes, that is,
1 to 2 nights of between 3 and 5 hours of time in bed,
35
but there
are no studies that have examined the impact of mild, chronic
sleep loss on exercise and sports performance in elite athletes,
that is, 7 to 14 days of between 5 and 7 hours of time in bed. In
healthy, untrained adults, 7 days of either 5 or 7 hours of time in
bed slows response time by 23% and 12%, respectively, when
compared with 9 hours of time in bed
15
; and 14 days of 6 hours of
time in bed increases the rate of errors on a response time task by
177% when compared with 8 hours of time in bed.
16
In the
present study, 38% of athletes obtained 6.5 hours of sleep or less
over an average of 12 (4) days. This level of habitual sleep
duration could impair aspects of cognitive function and self-
perceived capacity that are important for exercise and sports
performance, for example, longer response times in time-critical
sports, decreased time to fatigue in sports that require intermittent
and repeated bouts of exercise, an increase in decision-making
errors in any sport played over prolonged periods, and so forth.
35
However, very little is known regarding the impact of short
habitual sleep duration on exercise and sports performance. Short
habitual sleep duration could directly affect exercise and sports
performance through impairments in heart rate, minute ventila-
tion, and lactate concentration,
36
or it could indirectly affect
exercise and sports performance through alterations in mood,
motivation, and/or perceived exertion.
37,38
In the absence of a
Figure 5 —Mean (SD) (bars and lines) and individual cases (open circles) of habitual sleep onset time (A), habitual sleep offset time (B), and habitual
sleep duration (C) plotted as a function of individual sport or team sport. There was a main effect of sport type (ie, individual vs team sport, as indicated
by *) on habitual sleep onset time (F
1,173
= 9.15, P= .003; d= 0.5, medium), habitual sleep offset time (F
1,173
= 53.28, P<.001; d= 1.2, large), and
habitual sleep duration (F
1,173
= 13.1, P<.001; d= 0.6, medium).
8Sargent et al
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Figure 6 —Mean (SD) (bars and lines) with individual cases (open circles) representing habitual sleep onset (A), habitual sleep offset (B), and habitual
sleep duration (C) plotted for each sport. The outcomes of the post hoc comparisons between sports and the corresponding effect sizes are presented in
each panel. In panel B, differences between swimming and the other sports are indicated by sequential vertical marks on the top line, and differences
between triathlon and the other sports are indicated by sequential vertical marks on the bottom line. (Please note: The rank order in which sports are
presented on the x-axis differs between the 3 panels.)
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systematic evaluation of the relationship between habitual sleep
duration and exercise and sports performance, it is not possible to
confirm one explanation or the other.
Females are typically underrepresented in studies examining
the sleep/wake behavior in athletes. Despite a large sample
cohort in the present study (n = 175), only 17% (n = 30) were
women. Habitual sleep onset time was earlier in female athletes
compared with male athletes, but there was no difference in
habitual sleep duration between the sexes. Similarly, Leeder
et al
12
reported no difference in sleep duration between female
(n = 43) and male (n = 23) Olympic athletes. However, this
comparison—as was the comparison in the present study—
was not sport specific. That is, male and female athletes from
different sports were compared, rather than comparing sleep
variables between male and female athletes from the same sport.
Habitual sleep duration differs as a function of sport,
6
which
raises the possibility that potential sex differences in habitual
sleep duration may be obscured if comparisons are not confined
to athletes participating in the same sport. This is an area that
requires further investigation.
There are some delimitations that should be considered when
interpreting the results of the present study. Sleep need was
assessed using a single subjective question. Objective sleep need
can be assessed using sleep restriction and/or sleep extension
protocols.
39
However, these protocols are not feasible for use
with elite athletes because they require an individual to spend
multiple consecutive nights in a sleep laboratory. In the present
study, habitual sleep duration was based on nighttime sleep
episodes only—athletes were not required to record daytime
naps. It is possible that some of the athletes supplemented their
nighttime sleep with daytime naps. This would result in an
underestimation of habitual sleep duration. Napping is an effec-
tive strategy in some situations when athletes’nighttime sleep is
restricted
40
; however, the frequency of daytime napping in
athletes is typically low
6
and unlikely to substantially increase
total sleep duration.
9
Finally, activity monitors were used to
assess habitual sleep duration. These devices are considered
acceptable for monitoring sleep/wake behavior in the field,
but validation studies indicate that the devices can either over-
estimate or underestimate sleep duration by 18 (52) and 54
(36) minutes, respectively.
21,22
Consequently, the accuracy of
the devices should be considered when interpreting the values of
habitual sleep duration reported in the present study.
Practical Applications
The results presented here could be used by coaches and practi-
tioners as normative data to guide their athletes regarding appro-
priate sleep targets for duration and timing. Importantly, elite
athletes need ∼8 hours of sleep per night to feel rested, but
more than 70% of athletes do not obtain the sleep they need on
a regular basis. Coaches and practitioners should consider factors
that affect the timing of their athletes’sleep (eg, training start times,
competition schedules, travel, etc), which may be preventing their
athletes from obtaining the sleep they need. Potential strategies for
maximizing sleep duration by manipulating sleep timing include
(1) delaying the start time of morning training sessions and/or
minimizing the number of training sessions that start before 6 AM
whenever possible; (2) encouraging athletes to delay their wake-up
time the morning after an evening competition or training sessions,
if practical; and (3) providing athletes with targets for sleep timing
to help them achieve their optimal sleep duration where appropriate
(eg, sleeps that start between 22:00 and 22:30 h or end between
09:00 and 09:30 h).
Conclusions
Elite male and female athletes need 8.3 hours of sleep to feel rested.
However, a majority of athletes (71%) fail to meet this need on
most nights. The consequences of insufficient habitual sleep
duration for general health and cognitive performance are well
understood, but less is known regarding the impact of insufficient
habitual sleep duration on exercise and sports performance. In the
future, it will be important to determine whether increasing an
athlete’s habitual sleep is a feasible and efficacious strategy for
improving exercise and sports performance.
Acknowledgments
This study was financially supported by the Australian Research Council
under grant (LP0990371). The authors are grateful to the athletes and
coaching staff for their time and commitment during data collection.
Figure 7 —Mean (SD) (bars and lines) and individual cases (open circles) of habitual sleep onset time (A), habitual sleep offset time (B), and habitual
sleep duration (C) for male and female athletes. Habitual sleep onset was earlier in females than males (F
1,173
= 5.0, P= .03; d= 0.5, medium, as indicated
by *), but there was no difference between the sexes for habitual sleep offset time (F
1,173
= 2.65, P= .11; d= 0.3, small) or habitual sleep duration (F
1,173
=
2.15, P= .14; d= 0.3, small).
10 Sargent et al
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