The benefits of good sleep come into particular focus for athletes. Post-exercise recovery with extra sleep accelerates the building of muscle, strength, and endurance.
Research shows that athletic performance improves with sufficient sleep. Rested athletes are faster, more accurate, and have a quicker reaction time. Mild sleep deprivation does not negatively affect aerobic capacity, but it does affect reaction time.
The Stanford Sleep Disorders Clinic and Research Laboratory has attempted to quantify the effect of sleep on athletic performance. A study of swimmers asked to sleep 10 hours a day for six to seven weeks found notable improvements. This involved forcing the athletes to sleep longer than most people do to see if extra sleep in athletes undergoing heavy training had a benefit. Swim times were faster, and reaction times and turn times in the water improved. Kick stroke count increased as well.
A similar regimen (10 hours of sleep per day during heavy training) for football players also produced improvements. Sprint times declined and mood as measured by the POMS (Profile of Mood States) test (an indicator of physiological stress) increased. In addition to the swimming and football athletes Stanford has studied athletes from basketball, track and field, tennis, golf, and cross country. The evidence, usually based on small sample sizes, suggests more sleep results in improved physical performance.
The Effects of Sleep Extension on the Athletic Performance of Collegiate Basketball Players
Researchers have conjectured that long, heavy sleep impacts athletic performance due to the fact that growth hormones are released during deep sleep and the extra sleep encourages more hormone production.
Trainers recognize the benefits of sufficient and even long sleep for athletes in heavy training. Short sleep is likewise detrimental. Cutting two hours from the normal sleep time degrades athletic performance roughly the same as drinking enough to produce a blood alcohol level of 0.05. Competitive athletes often have sleep onset insomnia before an important event, due to nervousness.
Some top-level athletes attempt to cheat by taking supplements of human growth hormone. Natural increase of HGH can be promoted by both exercise and sleep. Physiologists speak of exercise-induced growth hormone response, which resistance training is known to cause. The load and frequency of the resistance influence the amount of hormone released.
Journal abstract: High exercise levels are related to favorable sleep patterns and psychological functioning in adolescents: a comparison of athletes and controls.
Does exercise make you sleep better? There is evidence that growth hormone (GH)-releasing hormone stimulates NREM sleep. Very heavy exercise experienced by world-class athletes shifts the sleep architecture. The REM latency – which is to say the time period after the person goes to sleep before REM starts – is longer, and the sleeper has less REM during the first half of the night than normally.
The stress hormone cortisol seems to promote REM sleep and exercise reduces cortisol levels.
The English Institute of Sport measured sleep parameters of some athletes at the 2012 London Olympics and found slightly worse sleep efficiency and fragmentation index than non-athletes in the same age range, although the difference was not dramatic and on the whole the athletes had numbers in the normal range.
Muslim athletes who fast during daylight hours during Ramadan are known to take a performance hit. It is not clear whether the change in eating patterns affect sleep duration, time, and quantity enough to make a difference in athletic performance.
Women endurance athletes are known to have menstrual irregularities, but we do not know of any attempt to explicitly work out the relationship among intense training, sleep patterns, and menstruation.
One way endurance athletes train involved sleeping in low air pressure environments to encourage the formation of red blood cells. The bed is inside a tent that simulates the atmosphere in the mountains. Altitude insomnia is known to affect people who travel to the mountains and there has been concern among sports medicine people that this practice may lower sleep efficiency so much as to outweigh any blood-building benefits. A study by Sports Medicine Australia found that although the effect on sleep was measurable, it varied greatly from person to person and was not great enough to cause the practice to be halted.
Does sleep make it easier to exercise or does exercise make it easier to sleep. Both. And human growth hormone is tied up in both.
Human growth hormone (often abbreviated HGH, or GH for growth hormone, or hGH) is an important part of the body’s endocrine system and is especially active in the growing child’s maturation. (It is not the only physiological factor that makes kids get taller.) HGH is released by the brain into the bloodstream during sleep, and its release is part of the repair and restoration function of sleep.
The hormone is a complex protein produced by the pituitary gland in the brain, and in addition to promoting growth in childhood, it helps maintain healthy bodily tissue even during adulthood. The pituitary gland releases growth hormone non-continuously – the release looks like a pulse. Sleep and exercise induce the release of the hormone.
In normal healthy people, the major period of HGH release is in the first period of Stage 3 sleep during the night.
If a person stays up all night when he or she normally sleeps, there is no surge in growth hormone release. After a period of sleep deprivation, there is extra hormone released when sleep is resumed, and the pattern departs from the normal pulse during slow-wave sleep.
Scientists did an experiment where they hid people away from daylight and other environmental cues that act as circadian hooks. The subjects were allowed to set their own sleep schedule which became disentrained from the 24-hr cycle. This experiment has been done many times, but in this case the scientists measured the blood levels of growth hormone and followed when the pituitary gland released the hormone. They found the peak levels of hormone released during sleep decreased significantly. The first slow wave sleep (SWS) period of the night was shorter and the first REM period happened sooner.
The researchers concluded that the timing of sleep stages can change the amount of hormone released during sleep.
In middle age, the brain starts producing lower quantities of growth hormone. This has spurred interest in use of supplemental hormones to keep the body young. The effectiveness of this is not widely accepted by credible medical authorities, and is not approved by the FDA. (Supplemental HGH is approved for some pathologies, but not for general aging.)
Elite athletes sometimes use HGH supplements (maybe the recombinant form called somatropin) with an eye toward improving performance. This use breaks the rules of many or most leagues and sporting authorities. It is similar to the use of steroids. Responsible doctors always oppose steroid use for performance edge because of the side effects. The side effects of growth hormone may not be as dangerous, but the medical community still looks down on this practice. However, the connection between HGH and sleep coupled with the connection between good sleep and enhanced athletic performance are too similar to be coincidental.
ESPN recently featured an article that floated the idea that sleep itself was a “magic pill” for athletic performance.
Smart trainers and world-class athletes understand the importance of regular sleep.
Elite athletes often suffer problems due to domestic or occupational schedules that do not permit normal sleep schedules and to rapid travel across multiple time zones (jet lag). Endurance athletes often have a problem with immuno-suppression and chronic reduction in sleep can contribute to this. Indeed, even in non-athletes, sleep deprivation can suppress the immune system.