Mysteries of Sleep
February 11, 2006
Americans are sleeping less than they used to, averaging only seven hours in bed a night. Close to 60 percent report that they have trouble sleeping a few nights every week.
Two Different Systems
Possible solutions to the problem could lie in the fact that sleep is regulated by two entirely different systems.
The sleep homeostat builds a need for sleep in a fairly linear fashion, based on how long you are awake and how active you are. The circadian rhythm, however, is tied to cycles of light and dark. Darkness causes the brain to secrete the sleep-inducing hormone melatonin.
Either of these cycles can be used to help those who have trouble sleeping. Bright lights or melatonin tablets can be used to affect the circadian rhythm. Exercise and heating the body (such as by taking a warm bath) can be used similarly on the sleep homeostat.
Pain, Depression, and Injury
Chronic sleep disruption can affect ability to learn, skills, memory, stamina, health, and safety. It is also, in all likelihood, the single biggest trigger for depression. Insomnia can cause irritability, headaches, and muscle pain. Job injury rates can increase 400 percent for the sleep-deprived, and 16 percent of absenteeism is associated with insomnia.