Sleep is essential for recovery of the brain and body, yet many athletes have problems falling asleep or may wake up during the night, then wake up in the morning not well rested.
A new critical review was published in the British Journal of Sports Medicine this week, in which a number of experts evaluate the evidence on sleep for athletes. Here is an interview with 2 of those authors: Dr Shona Halson and Prof Neil Walsh.
Sleep is always linked to recovery, but exactly does it do? How does it help us recover?
Sleep is essential for recovery of the brain and body. Sleep deprivation or restriction has negative effects on cognition, learning and memory consolidation and mental well-being, growth and repair of cells, metabolism of glucose and immune function. Sleep helps us to both recover from the previous day and prepare for the next day.
What exactly is sleep?
Sleep is defined as a reversible, naturally recurring state characterised by closed eyes, horizontal body position, reduced body movement, reduced responsiveness to external stimuli and a reduced breathing rate. During non-REM sleep, the brain is relatively inactive, although it is actively regulating vital functions, and the body is movable. In contrast, during REM sleep, the brain is highly activated, while the body is essentially paralysed.
What do we know about athletes sleep and why is it different from the average person?
The prevalence of poor sleep in athletes has been reported to be high among elite athletic populations who often experience disruptive training and competition schedules that limit the opportunity for sleep. This is characterised by habitual sleep durations <7 hours, sleep dissatisfaction, unrefreshing sleep, long sleep onset latency (time taken to fall asleep), day-time sleepiness and day-time fatigue. Studies reporting sleep quality show that 50%–78% of elite athletes experience sleep disturbance and 22%–26% suffer highly disturbed sleep.
The prevalence of poor sleep in athletes has been reported to be high among elite athletic populations
There is not a great deal of quality research that has compared athletes to the average person, but the poorer sleep seen in athletes may be due to sport-specific factors such as training (especially early morning training starts), competition (stress of competing and/or late night games) and travel/jetlag. Athletes of course also engage in societal behaviours such as Smartphone use, social medial and gaming.
How does exercise/training affect sleep?
We don’t know much about training itself in athletes, however intensified training has been shown to have small reductions in sleep quality and quantity. In the general population, it is well accepted that exercise is good for sleep. So perhaps there is a line at which too much exercise becomes bad for sleep.
How does eating affect sleep?
There is small evidence that some protein-rich foods may improve sleep as well as high GI foods taken at least 4 hours before bed. Importantly, many athletes wake to go to the bathroom if they are over-hydrated. Also, athletes may wake from feelings of hunger.
In which sports is sleep poorest?
Generally speaking sleep is poorest in sports with early training times and/or late night competitions. Sports that compete more than once per week and travel extensively such as NBA or soccer are likely to experience challenges to obtaining good sleep.
What is the advantage of measuring sleep?
The advantage of measuring sleep is not in the measurement per se, but in the ability to provide individual feedback to an athlete to improve sleep. This might encourage the athlete to try to avoid behaviours that might disturb their sleep (smartphone use, social media, caffeine).
What are the disadvantages of measuring sleep?
There is definitely a risk of orthosomnia (excessive concern/worry/perfectionism relating to sleep). My personal preference is not to monitor sleep objectively with a device that provides instantaneous feedback (and sometimes unvalidated ‘scores’ of recovery or sleep) for long periods of time. Especially in athletes who may have excessive worry about their sleep. This may cause more harm than good and providing an athlete with data the morning of an Olympic Final or World Cup Final might not be helpful. I personally prefer discreet blocks of monitoring where I provide the feedback and interpretation of the sleep data.
There is a risk of orthosomnia (excessive concern/worry/perfectionism relating to sleep) when measuring sleep
How accurate are the sleep measuring devices ?
Most activity monitors are reasonable at measuring sleep, but not so good at wake. So they often overestimate the amount of wake. If an individual has a lot of wake during sleep, the overestimation will be greater. I think it is important to understand the limitations of these devices, but it is much important to provide the appropriate feedback to an athlete. Most devices don’t provide feedback and many practitioners measure sleep, but do not feedback to the athlete ways to improve their sleep.
What advice would you give practitioners who work with a teams?
Education and screening is vital (Figure 2 in the paper) and engage with an expert who can really help the athlete improve and optimise their sleep. I also think it is important we look at we do as practitioners and how we can protect sleep. For example, avoiding unnecessarily early training times and optimising travel schedules.
What are the most important recommendations for athletes to improve sleep?
I would refer to Box 3 from the paper here which shows five tips to educate athletes on the importance of sleep, which are:
Night-time sleep quantity
Daytime sleep quantity (naps)
Good sleep hygiene
Sleep and train in line with chronotype
Caution when using sleep monitors
What are the 3 most important do’s and the 3 most important don’ts?
For do’s I would refer to Box 2 in the paper which shows a summary of the sleep toolbox for practitioners:
Provide sleep education for athletes
Screen athletes for sleep problems
For don’ts, I would say:
Realise that sleep is important, but try not to be excessively perfectionist about it.
Never stay up late for something you wouldn’t get up early for (don’t stay up on SmartPhones/social media).
Don’t monitor sleep without providing appropriate feedback - it may not help and may actually harm sleep.
Walsh NP, Halson SL, Sargent C, et al. Sleep and the athlete: narrative review and 2021 expert consensus recommendations. British Journal of Sports Medicine Published Online First: 03 November 2020. doi: 10.1136/bjsports-2020-102025