The importance of quality Sleep

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Whether you want optimal health and/or optimal recovery from exercise, sleep is one of the best tools you have. AND….. it’s free!

Sleep involves more than just getting some much needed rest after a busy day. It is the period when the body performs essential maintenance, rebuilding of tissue, etc… The amount of sleep a person needs can vary from five to nine hours, however it seems the average adult needs approximately eight hours of quality sleep. The majority of functions that take place when asleep seem to be generally controlled by hormonal function, e.g. melatonin, testosterone, cortisol and growth hormone. The latter two are of particular interest to the athlete, because if these are out of kilter it can result in much waste of training effort. Before these are discussed we should examine what sleep actually is.

Sleep Stages

 

Sleep occurs in five stages (Ref 1) that recycle many times during the rest period.

Stage 1 involves the muscles beginning to relax and breathing becomes shallower. It can last from ten seconds to ten minutes. It almost seems like a transition period between full wakefulness and falling asleep.

Stage 2 may last up to twenty minutes and sees the body’s temperature drop and the heart rate slow down. The body is now ready for deep sleep.

Stage 3 is the transitional period between light sleep and deep sleep.

Stage 4 is when a person is completely immersed in the deep sleep state and can last up to thirty minutes.

Stage 5 (also known as REM or Rapid Eye Movement) is the stage when dreaming can take place. REM sleep is characterized by eye movement, increased respiration rate and increased brain activity. 1 Interestingly, the major muscle groups are paralysed despite the increased brain activity during REM sleep.

After stage 4, the sleep cycle reverts back to stages 3 and 2 before progressing to stage 5. The normal sleep cycle will then look like this: 1→2→3→4→3→2→5 and it is repeated many times during the night.

Reasons to get Quality Sleep

The negative health implications of not getting enough quality sleep are:

  • Impaired memory, reduced learning of sports skills, increased reaction time, lower attention span, less ability to adapt to unfamiliar circumstances. (Ref 2)
  • Compromised immune system. (Ref 3) Not getting enough sleep can make a person more susceptible to everyday, nuisance infections like cold and flu, but also vulnerable to cancer and diabetes.
  • Less able to deal with stress. (Ref 4) Aggression and irritability can be increased which makes handling difficult situations even more challenging. This can even lead to a chain reaction of stress leading to sleep disruption, leading to more mental anxiety, and so on.
  • Cardiovascular risk (Ref 5) – Studies have shown that people who get too little sleep may wake up with higher resting heart rates and increased blood pressure. This can put the cardiovascular system under strain over a long period.
  • Weight gain: Studies (Ref 6) have shown that sleep deprivation exhibits signs of glucose intolerance, which is an early indicator of insulin resistance and diabetes (Type II). Other studies (Ref 7) have shown that major hormonal disruption associated with increased appetite occurs with lack of sleep.
  • Serious hormonal disruption associated with increased ageing, reduced weight control and impeded body tissue rebuilding.

Tips for a good night’s sleep

  • Avoid eating within two hours of going to sleep, particularly carbohydrates. As the carbohydrates can be broken down into glucose, the spike in blood sugar levels can stimulate wakefulness. (Ref 8)
  • Avoid alcohol. The commonly taken “nightcap” can seem to relax one and help prepare for sleep. However, alcohol lightens sleep, particularly in stage 4 which is the key recovery stage after physical activity.
  • Minimise stimulating activity, e.g. television before sleep as this can delay falling off to sleep.
  • Try to have a bedtime routine. Having regular “going to bed and getting up” times and sticking to them can help to regulate and normalise sleeping patterns.
  • Sleep in complete darkness. Use heavy curtains to block out all street light and face an electric alarm clock down to hide its light.
  • The temperature and ventilation of the bedroom is important. Cool (not cold) usually is best.
  • A protein drink containing a slow-releasing protein e.g. casein, can be helpful in inducing sleep as it contains the amino acid tryptophan. It may also help in recovery and rebuilding of muscle tissue. (Ref 9)

To read more about the importance of sleep, and the implications of lack of sleep, check out, “Training and Optimal Health for Sports.”

 References

  1. http://psychology.about.com/od/statesofconsciousness/a/SleepStages.htm
  2. Science of Sports Training, Tom Kurz page 122
  1. Optimal Muscle Performance and Recovery, by Edmund R. Burke, page 226
  2. http://psychology.about.com/od/statesofconsciousness/tp/reasons-to-sleep.htm
  3. Take Control of your Health, by Dr. Joseph Mercola, page 193
  4. Spiegel, K. Impact of sleep debt on metabolic and endocrine function. The Lancet. October 23, 1999. 354:1435-1439.
  5. Spiegel, K. et al. Brief Communication: Sleep Curtailment in Healthy Young Men Is Associated with Decreased Leptin Levels, Elevated Ghrelin Levels, and Increased Hunger and Appetite. Annals of Internal Medicine. December 7, 2004. 141:846-851.
  6. Take Control of your Health, by Dr. Joseph Mercola, page 197
  7. http://www.umm.edu/sleep/sleep_hyg.htm#e
  8. Exercise Physiology, Energy, Nutrition, and Human Performance. McArdle, Katch & Katch, fifth Ed, p.g. 42
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