Sleep: How It Can Decrease Injury and Improve Performance.

It’s a little bit ironic that I write this blog about the negative effects of poor sleep quality on injury, illness and sports performance when I barely scrape together 6 hours sleep a night due to my darling 18-month old daughter’s sleeping habits. The only difference is that the level of my sporting prowess is limited to taking my dog for a brisk 45minute walk around the park each day, and bending over each morning to tie up my shoelaces.

For elite athletes however, sleep is a crucial part of their preparation for sport and an even more crucial part of their recovery from matches and injury. For amateur and community level athletes however it is a frequently over-looked strategy to improve performance and assist in recovery from injury. I often ask my patients how they recover from training and games, and they will rattle of “stretch, ice bath, foam roll, hydrate (+/- a couple of post-games beers), eat well, etc etc”…but rarely do I hear “I try to get at least 8 hours or more sleep per night”.

I posted earlier this week to my social media accounts a link to a paper that concluded that teenage athletes who get less than 8 hours of sleep each night, increase their injury risk by 1.7x, compared to those who get 8 or more hours sleep [endif]--(1). Furthermore, another study I found reported sleeping less than 6 hours or less per night was associated with fatigued-related injuries among young soccer basketball, football, soccer and running athletes [endif]--(2). As a result, I looked deeper into the research about sleep, recovery and performance and found further evidence to say that we should be asking our patients and sub-elite athletes about their sleeping habits and educating them on the power of sleep to assist them with their injury prevention/rehab and training goals.![endif]--![endif]--

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The American National Sleep Foundation recommends that the optimal sleep duration is 7-9 hours per night, but sleep quantity is not the only important factor. Sleep quality and timing of sleep are key components to sleep, and any disturbance to 1 of these 3 factors can negatively affect the post-exercise recovery process (3). Physiologically, sleep loss impairs, although not limited to, the following:

- Growth hormone release and muscle protein synthesis: This means the ability for skeletal muscle to adapt and repair, which also has a direct impact on training adaptations such as speed, endurance, strength and power (3-5).

- The learning of new skills and memory: Sleep is crucial for memory consolidation and motor learning (2). Sport is a constantly evolving process, where not only do you need highly developed physical attributes, but sport also requires high levels of motor learning, skill acquisition, strategy, decision-making, cognition and memory to carry out tasks which ultimately influence performance (3 . title="Simpson, 2016 #450"4).

In elite and sub-elite athletes late night training or late night games are common, and this has been shown to negatively affect sleep duration and quality in professional soccer players, when compared to training days and day matches [endif]--(5 - 6). Reasons for this have been postulated [endif]--(5):![endif]--![endif]--[endif]--[endif]--

- Bright lights: Light has an inverse relationship with the sleep hormone melatonin; therefore light/artificial light may suppress melatonin and negatively affect sleep.

- 79% of professional soccer players also reported using smartphones, watching TV, using laptops prior to sleep which all have artificial lighting that reinforces the above point.

- Furthermore, technology use prior to sleep may not allow the athlete to “switch-off” prior to bed, with frequent users of social media reporting almost 1 hour per night less sleep.

- Caffeine is frequently used by athletes to enhance stamina, mental acuity and performance during games, but physiologically, caffeine inhibits melatonin secretion thus effecting sleep behaviour (7).

In regards to sporting performance, sleep behaviours have discovered some interesting results (4):

- A group of basketball players were encouraged to increase their sleeping habits from an average of 6.5hrs per night to 8.5hours per night. At the end of the 7 week trial; speed tests increased by 5%, free throw accuracy increased by 9% and 3-point accuracy improved by 9%.

- Tennis players were encouraged to increase sleep duration by 2 hours per night, which improved their serving accuracy by 5% over the trial period. title="Sufrinko, 2015 #446"

Finally, the effect of sleep quality prior to a concussion and its effect on post-concussion symptoms is something that we should all be aware of (8):![endif]--[endif]--

- Adolescent and young athletes (mean age 17yrs) with poor sleep behaviour (difficulty falling to sleep, sleeping less than usual) prior to sustaining a concussion were compared against those who had good sleep behaviour prior to concussion.

- The poor sleep group performed significantly worse on visual memory, verbal memory and reaction time compared to the controls, in particularly within the first 2-5 days post-concussion, with reaction time being significantly slower up to 14 days after the concussion.

- In regards to concussive and sleep-related symptoms, the poor sleep group consistently showed increased symptoms during the first 14 days post-concussion.

- Conclusion: those athletes with pre-injury sleep difficulties performed worse on neurocognitive tests and had worse concussive symptoms after the injury, compared to those athletes that did not have poor sleep difficulties, especially reaction time tests up to 14 days post-concussion. title="Simpson, 2016 #450"

What this information shows us is that we need to be screening our athletes sleep habits regularly throughout the competitive season, so that we are aware of the potential ramifications of concussion, and subsequent slower recovery time of their reaction time and verbal memory. Importantly to note, in this study neurocognitive test results lagged behind symptom resolution, which highlights the need for more thorough neurocognitive testing of the concussed player, rather than allowing them to return to sport in the absence of symptoms.

In summing up this blog, sleep behaviours have a significant effect on injury recovery, training adaptation, neuro-cognition and the ability to perform sport at an optimum level. In my opinion, not only should we be monitoring and educating our elite athletes on their sleep behaviours, but ALL of our patients from the semi-elite junior athlete, to the weekend warrior, to the sedentary office worker.

Here are simple strategies recommended by Simpson et al (2016) for all of our patients and athletes to optimise their sleep patterns 4):

1) Encourage 7-9 hours per night and consider naps during the day if less than 7 hours sleep per night

2) Sleep in cool (but not cold), dark room

3) Avoid using electronics or personal devices in bedroom

4) Limit technology use 1 hour before bed

5) Reduce caffeine after lunch, and minimise alcohol at night

As always please feel free to share this post far and wide. Injury prevention and improved sporting performance are huge passions of mine, particularly in the adolescent athlete, and the more doctors, physios, exercise physiologists, S&C coaches, personal trainers, players, parents, coaches that get on board with this information and understand the benefits and power of sleep, the better performances we will see on the field, and the less injuries I’ll see in the clinic!

References:

1. Milewski MD, Skaggs DL, Bishop GA, Pace JL, Ibrahim DA, Wren TA, et al. Chronic lack of sleep is associated with increased sports injuries in adolescent athletes. Journal of pediatric orthopedics. 2014 Mar;34(2):129-33. PubMed PMID: 25028798. Epub 2014/07/17. eng.

2. Luke A, Lazaro RM, Bergeron MF, Keyser L, Benjamin H, Brenner J, et al. Sports-related injuries in youth athletes: is overscheduling a risk factor? Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine. 2011 Jul;21(4):307-14. PubMed PMID: 21694586. Epub 2011/06/23. eng.

3. Fullagar HH, Duffield R, Skorski S, Coutts AJ, Julian R, Meyer T. Sleep and Recovery in Team Sport: Current Sleep-Related Issues Facing Professional Team-Sport Athletes. International journal of sports physiology and performance. 2015 Nov;10(8):950-7. PubMed PMID: 25756787. Epub 2015/03/11. eng.

4. Simpson NS, Gibbs EL, Matheson GO. Optimizing sleep to maximize performance: implications and recommendations for elite athletes. Scandinavian journal of medicine & science in sports. 2016 Jul 1. PubMed PMID: 27367265. Epub 2016/07/02. Eng.

5. Nedelec M, Halson S, Abaidia AE, Ahmaidi S, Dupont G. Stress, Sleep and Recovery in Elite Soccer: A Critical Review of the Literature. Sports medicine (Auckland, NZ). 2015 Oct;45(10):1387-400. PubMed PMID: 26206724. Epub 2015/07/25. eng.

6. Fullagar HH, Skorski S, Duffield R, Julian R, Bartlett J, Meyer T. Impaired sleep and recovery after night matches in elite football players. Journal of sports sciences. 2016 Jul;34(14):1333-9. PubMed PMID: 26750446. Epub 2016/01/12. eng.

7. Fullagar HH, Skorski S, Duffield R, Hammes D, Coutts AJ, Meyer T. Sleep and athletic performance: the effects of sleep loss on exercise performance, and physiological and cognitive responses to exercise. Sports medicine (Auckland, NZ). 2015 Feb;45(2):161-86. PubMed PMID: 25315456. Epub 2014/10/16. eng.

8. Sufrinko A, Pearce K, Elbin RJ, Covassin T, Johnson E, Collins M, et al. The effect of preinjury sleep difficulties on neurocognitive impairment and symptoms after sport-related concussion. The American journal of sports medicine. 2015 Apr;43(4):830-8. PubMed PMID: 25649087. Epub 2015/02/05. eng.

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