From Ergo Log
If athletes force themselves to sleep two hours longer every day, their reaction speed increases and they get faster. Sleep researchers at Stanford University in the US discovered this when they performed experiments with basketball players.
Too little sleep leads to increased body fat, reduced testosterone levels, and decreased oxygen uptake, and animal studies have shown that it leads to muscle decay as well. On top of this, your immune system works better if you get enough sleep, and there are indications that good-quality sleep can extend your life expectancy.
So it's logical that athletes perform better if they make sure they don't miss out on sleep. But can athletes improve their performance by going a step further? By making sure they get lots of extra sleep? In 2011 Cheri Mah of Stanford University published in Sleep the results of a human study that showed this could be the case.
Mah used 11 students from the basketball team for her experiment. She got them to increase the amount of sleep they got to 10 hours a day over a period of 5-7 weeks. Before they started on the 'sleep extension' the subjects all slept just under eight hours a day. They thought that this was enough sleep.
Although the textbooks say that eight hours' sleep is enough, Mah observed that increasing the amount of sleep had a positive effect on the players. She used the Psychomotor Vigilance Task test to measure the players' reaction times, and discovered that these became faster as a result of more sleep.
In the Psychomotor Vigilance Task the subjects look at a black screen. When a point of light appears they have to press a button as fast as possible.
Before starting to sleep longer the athletes had an average of 16.2 seconds for an 86-m sprint. Extending their sleep reduced this to 15.5 seconds.
The subjects also found that they felt better for more sleep: less angry, depressed, stressed, tired and confused, and they had more energy. In addition their aim became better and more accurate.
"This study reveals an athlete's inability to accurately assess how much sleep one actually obtains each night, thus leading to a misperception regarding the duration of sleep that constitutes adequate nightly sleep time", the researchers conclude.
Sleep. 2011 Jul 1;34(7):943-50.