Sleep is considered vital to our health and well-being. It is critical for our physiological and cognitive functioning. Elite athletes experience high training and competition demands, and can often be exposed to various situations that cause sleep deprivation. Examining their sleep performance and intervention strategies can have applications for the general athletic population.
We reviewed the research paper “From pillow to podium: a review on understanding sleep for elite athletes”, by Shannon O’Donnell, Christopher M Beaven, Matthew W Driller, published in 2018 .
Why Sleep is Important for Athletes
As athletes training demands increase, the role of sufficient recovery becomes integral to improving their performance between training sessions.
Sleep has been recognised as one of the most effective recovery strategies available to athletes, and is often neglected.
Being able to measure your sleep is a good starting point. Research has found that the use of wristwatch devices are effective in measuring and assessing sleep for the general population.
Polysomnography, where body functions are measured through scalp and skin, is the “gold standard”, however a review article showed 91% to 93% agreement with wristwatch devices (Ancoli-Israel et al).
Physiology of Sleep for Athletes
Our bodies are based on rhythms, with circadian rhythms observed in most of our physiological processes. One of our fundamental rhythms, characterised by the 24-hour day-night cycle, is the sleep-wakefulness cycle.
The sleep-wakefulness cycle allows the body to recover from the day, enabling us to wake up feeling alert. Many hormonal responses take place in the lead up to and during sleep. One important response for athletic recovery is growth hormone.
Growth hormone plays an important role in muscle growth and repair. 95% of the daily production of growth hormone is released during deep (or non-REM) sleep. Deep sleep is when the body actively repairs and restores itself.
Two main hormones that impact our athletic performance are cortisol and testosterone - they are essential for muscle adaptation, specifically muscle growth. Both these hormones follow a circadian rhythm and are affected following a lack of sleep. With insufficient sleep our bodies will increase the secretion of cortisol and this will impact our secretion of testosterone too.
Sleep and Cognitive Performance
Elite athletes have high levels of cognitive processing in their sports. High brain activity during REM sleep is associated with memory consolidation and learning of motor skills. The quantity and quality of sleep the night following a memory task has been positively correlated to recall and retention, of that memory task, the next day.
Sleep and Injuries
Sleep deprivation has been shown to reduce reaction time, cognitive function, and affect mood. This is associated with an increased risk of injury.
A study by Milewski et al, on 112 adolescent athletes over a 21-month period, showed that the strongest predictor of injury was <8 hours of sleep per night. Athletes who slept <8 hours per night had 1.7 times greater risk of being injured than those athletes that have ≥8 hours of sleep per night.
Napping can be used to reduce sleep debt. There are two “ideal” time durations for a nap; less than 20 minutes to reduce the likelihood of waking up during deep sleep, or 90 minutes to complete a sleep cycle (deep and REM).
For competitive athletes, napping has been found to be an effective strategy on competition days to improve performance.