Sleep Deprivation Can Hinder Sports Performance
Logic would say that getting enough sleep is important for optimal sports performance, but there wasn't much evidence to support this theory -- until now. Some recent studies have found that that sleep deprivation can slow glucose metabolism by as much as 30 to 40%.
Eve Van Cauter, Ph.D., from the University of Chicago Medical School, studied the effects of three different durations of sleep in 11 men ages 18 to 27. For the first three nights of the study, the men slept eight hours per night; for the next six nights, they slept four hours per night; for the last seven nights, they slept 12 hours per night.
Results showed that after four hours of sleep per night (the sleep deprivation period), they metabolized glucose least efficiently. Levels of cortisol (a stress hormone) were also higher during sleep deprivation periods, which has been linked to memory impairment, age-related insulin resistance, and impaired recovery in athletes.
Van Cauter said that after only one week of sleep restriction, young, healthy males had glucose levels that were no longer normal and showed a rapid deterioration of the body's functions. This reduced ability of the body to manage glucose is similar to those found in the elderly.
Most of what we know about sleep deprivation has to do with immune function and brain function. This study is interesting because it shows that sleep deprivation can negatively impact physiology that is critical for athletic performance -- glucose metabolism and cortisol status. While no one completely understands the complexities of sleep, this (and other research) indicates that sleep deprivation can lead to increased levels of cortisol (a stress hormone), decreased activity of human growth hormone (which is active during tissue repair), and decreased glycogen synthesis.
Other studies link sleep deprivation with decreased aerobic endurance and increased ratings of perceived exertion.
What does this all mean?
Glucose and glycogen (stored glucose) are the main sources of energy for athletes. Being able to store glucose in muscle and the liver is particularly important for endurance athletes. Those who are sleep deprived may experience slower storage of glycogen, which prevents storage of the fuel an athlete needs for endurance events beyond 90 minutes.
Elevated levels of cortisol may interfere with tissue repair and growth. Over time, this could prevent an athlete from responding to heavy training and lead to overtraining and injury.
Obviously, more research is necessary. But this study indicates that a chronic lack of sleep may affect metabolic function. For the endurance athlete, proper sleep during heavy training and before competitions certainly may help and is unlikely to cause harm.
Why Athletes Need Rest and Recovery
It is the alternation of adaptation and recovery that takes the athlete to a higher level of fitness. High-level athletes need to realize that the greater the training intensity and effort, the greater the need for planned recovery. Monitoring your workouts with a training log, and paying attention to how your body feels and how motivated you are is extremely helpful in determining your recovery needs and modifying your training program accordingly.======================
Why You Should Try to Avoid Shift Work and Irregular Sleep
By Dr. Ben Kim on July 31, 2008
According to a study published in the August 1, 2007 issue of the journal Sleep, rotating shift workers have significantly lower levels of serotonin (precursor to melatonin) than people who work regular day shifts. A total of 683 men of European ancestry were evaluated for this study; 437 were day workers, and 246 were rotating shift workers.
Serotonin is a hormone that circulates throughout your body. It is also a neurotransmitter in your central nervous system (brain and spinal cord). A chronically low level of serotonin is associated with many health challenges, the most common of which are:
- Poor quality sleep
- Problems with body temperature regulation
- Tendency to feel depressed and anxious
- Poor ability to regulate anger and aggression
- Sexual difficulties
The findings of this most recent study confirm the importance of maintaining a regular circadian rhythm by resting when you are tired, and striving to maintain a regular routine of sleeping.
If your current life circumstances do not allow for a regular sleeping routine, you should at least strive to acquire restful sleep whenever your schedule allows you to. Here are a few suggestions on how to accomplish this while working on a rotating shift schedule:
- Within your irregular sleep schedule, strive to maintain a steady routine of eating, getting cleaned up, spending time with loved ones, and taking care of necessary errands before going to sleep.
- When you must sleep while the sun is out, use a sleeping mask or dark and heavy curtains to provide a dark sleeping environment. A dark sleeping environment is important to your body's ability to produce serotonin.
- Do everything you can to minimize potential disruptions during sleep time, like turning the phone ringer off, posting a 'no solicitations' sign outside your home or apartment, and wearing earplugs.
For more information on this topic, including suggestions on how to support your health via high quality sleep, view the following articles:
Why You Should Sleep in Darkness
How Much Sleep Do You Really Need to Be Healthy?
Healthy Foods that Promote Deep Sleep
Study Abstract:
http://www.journalsleep.org/ViewAbstract.aspx?citationid=3306
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