Reaction time, coordination and accuracy
It's in Stage 5 (REM) sleep where our brains recovery, learning and development occurs. We create new nerve pathways to consolidate and repair memories, skills and process information. Side note - it's also where we release testosterone (in both men and women). Research suggests that sleep deprivation delays the signals which travel along these pathways, decreasing our coordination and accuracy (2). So much so that inadequate sleep has been likened to being drunk! Williamson and Feyer (2000) demonstrated the longer the duration without sleep (up to 23 hours), performance in cognitive tasks, motor skills, speed and accuracy decreased to levels equivalent to a blood alcohol content of 0.1%. Twice the legal driving limit in Australia!
The duration of REM sleep increases as the night progresses, with the longest duration occurring just before waking. So get to bed early to ensure you get the beneficial effects on mental performance more REM sleep brings.
Injury & illness
Decreased sleep has been associated with an increased risk of injury and illness. Inadequate sleep is immunosuppressive, increasing our risk of upper respiratory tract infections. In a study of 164 adults administered nasal drops containing rhinovirus, those who slept for less than 5hrs were 4.5 times more likely to develop an illness than those that slept for greater than 7hrs (4).
Being sick or injured reduces training availability and is obviously something we want to avoid. The underlying mechanism for increased injury with sleep loss is unclear but is likely due to cognitive impairment and decreased reaction time, along with higher levels of fatigue. All of which can increase an athletes risk of injury.
Mental stamina and mood
Striving to be fitter, faster and stronger doesn’t just require physical effort, it also requires mental stamina. Feeling mentally drained will impact your mood and we all know that missing out on a good nights rest can alter how we think and feel. People who sleep for less than five hours are often sadder, angrier and more stressed (2) which is linked with low motivation and decreased sports performance (5).
Not a lot is known about sleep deprivation and its effect on short, sharp, anaerobic power type exercise, but a number of studies have shown decreased endurance performance (6, 7, 8, 9). Sleep loss clearly resulted in increasing 3km time trial duration in cyclists (7), decreased time to exhaustion in volleyball players (6) and decreased treadmill run distance covered in a 30 minutes self-paced test (9). This appears to be due to an increase in our perception of effort (how hard you feel you're working) (8). It may also be due to an alteration in substrate availability as pre-exercise muscle glycogen (our carbohydrate fuel tank) has been found to be decreased after sleep deprivation (10).
Improve sleep efficiency
Multiple studies show the significant implications sleep deprivation has on performance. From impaired accuracy, coordination and reaction time, fatigue, inadequate recovery, to increased risk of injury and illness. So what can we do to improve our sleep efficiency - both duration and quality?
- Get to bed earlier, aiming to get 7-9 hours of sleep every night.
- Stop using your phone in bed. The blue light it emits affects our normal sleep hormone production (melatonin)
- Ensure all of your devises are set up with night mode so they switch to a more warm, orange hue after sunset.
- Make your sleep environment comfortable, dark, cool and quiet
- Establish a regular sleep routine
- Eat foods that assist with promoting sleep - more on this next time!
Next up - we take a look at food to boost sleep performance. Stay tuned!
1. Hirshkowitz et al., (2015). National Sleep Foundation's updated sleep duration recommendations: final report. Sleep Health: The Journal of the National Sleep Foundation. 1(4), 233-243
2. Bird, S, P. (2013). Sleep, recovery, and athletic performance: a brief review and recommendations. Journal of Strength and Conditioning. 35:43-47.
3. Williamson, A., Feyer, A. (2001). Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. Occupational and Environmental Medicine, 57: 649-655.
4. Prather, A., Janicki-Deverts, D., Hall, M. and Cohen, S. (2015). Behaviuorally assessed sleep and susceptibility to the common cold. Sleep. 38: 1353-1359.
5. Totterdell, P., Reynolds, S., Parkinson, B., & Briner, R. (1994). Associations of Sleep with Everyday Mood, Minor Symptoms and Social Interaction Experience. Sleep, 17(5), 466-475.
6. Azboy, O, Kaygisiz Z. (2009). Effects of sleep deprivation on cardiorespiratory functions of the runners and volleyball players during rest and exercise. Acta Physiologica Hungarica. 96, 29-36.
7. Chase et al. (2017). One night of sleep restriction following heavy exercise impairs 3-km cycling time-trial performance in the morning. Applied physiology, nutrition, and metabolism. 1-7
8. Fullagar, H, H, Skorski S, Duffield R, et al. (2015). Sleep and athletic performance: the effects of sleep loss on exercise performance, and physiological and cognitive responses to exercise. Sports Med. 45, 161-86.
9. Oliver, S, Costa, R, Laing, S, et al. (2009). One night of sleep deprivation decreases treadmill endurance performance. European Journal of Applied Physiology. 107, 155-61.
10. Skein, M, Duffield, R, Edge, J., et al. (2011). Intermittent-sprint performance and muscle glycogen after 30 h of sleep deprivation. Medicine and Science in Sports & Exercise; 43: 1301-11.
11. Watson, A. (2017). Sleep and Athletic Performance. Current Sports Medicine Reports, 16(6), 413-418.