In my “Recovery” blog (www.dc-injuryclinic.co.cuk/Recovery), I mentioned briefly “every bodies favourite part of Recovery – SLEEP!”. In this blog I will expand on the importance of sleep, particularly (but not solely) for the athlete, and talk a little about the physiology of what happens during our dormant state.
Athletes, coaches and therapists are becoming more aware that sleep deprivation can hinder athletic performance, but it is also a very real issue for non athletes, with some reporting that tiredness is as big an influence when driving as alcohol (ref 1).
A lack of ‘quality’ sleep has been show to influence:
- Pain perception
- The Immune system
- Inflammatory response
- Carbohydrate metabolism
- Protein synthesis
But what do we mean by ‘quality’ sleep?
It has been shown that when we sleep we go through 2 stages: rapid eye movement sleep (REM) and nonREM (NREM) sleep. REM sleep is characterized by – unsurprisingly – rapid eye movements and a low-amplitude EEG (electroencephalogram; recording of brain activity). This accounts for approximately 18–22% of total sleep time; this amount decreasing with age.
NREM sleep – or Slow Wave Sleep (SWW) – is characterized by slow wave activity with a relatively high amplitude EEG reading, and is further divided into four stages of sleep; stage 1 considered “light sleep” and stages 3 and 4 considered “deep sleep”.
SWS is thought to play an important role in cerebral restoration and recovery in humans. It is the construction phase for ‘restoration’ of the mind-body system, effectively rebuilding itself after each day. Growth hormones are secreted to facilitate the healing of muscles as well as repairing damage to any tissues. Also, glial cells within the brain are restocked with sugars to provide energy for the brain. SWS is thought to be involved in the maintenance and consolidation of sleep (3), meaning the more sleep we have, the better sleepers we become…at least in theory. The opposite also being true, as I’m sure fellow parents of young children will attest to!
Although there are no hard and fast rules as to how much sleep humans need, the general consensus seems to be that 7-9 hours is optimum for adults (18+ yo) (4). An interesting study was carried out amongst adolescents (ave. age 15 yo; famous for their sleeping ability!) that showed athletes who slept on average 8 hours or more per night, were 1.7 times less likely to have had an injury when compared to those that slept less than 8 hours per night (5).
So what can we do to encourage good quality sleep? Below is a useful info-graphic by sports scientist Yann Le Meur (@YLMSportScience).
‘Sleep Coach’ Nick Littlehales also has an excellent website – sportsleepcoach.com. On his blog ‘THE IMPORTANCE OF SLEEP IN SPORTS’, he says that “strategic napping can have a positive impact. Diet is also another factor that has a huge impact on our sleep. Foods high in carbohydrate such as white rice, pasta, bread, and potatoes have been found to promote better sleep by improving sleep-onset latency (how long it takes to fall asleep) and increasing levels of tryptophan [essential amino acid in humans, essentially building blocks for recovery. DC] in the brain. Foods containing large amounts of tryptophan such as seaweed, soy protein, spinach, and pork have been linked with being a sleep inducer.
In a recent study, it was found that diets high in carbohydrate resulted in shorter sleep latencies, diets high in protein resulted in improved sleep quality, diets high in fat have a negative influence on total sleep time and when total caloric intake is decreased our sleep quality is disturbed.”
So sleeping isn’t cheating, far from it; treat it as part of – a very important part of – your training, and more importantly your well-being.
Of course if you are really struggling to sleep, you could always re-read this blog….over….and over…and…. ZZZZzzzzzzz
- 1. http://www.telegraph.co.uk/motoring/news/8269657/Being-tired-behind-the-wheel-as-bad-as-being-drunk.html
- 2. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC297368/
- 3. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2824210/
- 4. http://sleepfoundation.org/how-sleep-works/how-much-sleep-do-we-really-need
- 5. Milewski MD et al. 2014
N.B. There are no ‘one size fits all’ style quick fixes in most injury scenarios, so these article shouldnt be seen as such. They are merely guides to a better understanding of how our bodies work.
For more information please visit www.dc-injuryclinic.co.uk