Sleep is Essential to the Workings of Every Organ.

But it's only in the last half a dozen years that studies have begun to link chronic partial sleep deprivation to serious physical health consequences.

Sleep is essential to the workings of every organ. And it seems that the connection between sleep and health starts at the brain's central command post, the hypothalamus. There, sleep or lack of it can work to activate, or inhibit, hormone production. There, too, is where the body gets the signal to go to bed, to wake up and to adjust temperature, blood pressure, digestive secretions and immune activity.

Inadequate sleep works on hormone production in other areas as well. Without enough sleep, the central nervous system becomes more active, inhibiting the pancreas from producing adequate insulin, the hormone the body needs to digest glucose.

A groundbreaking study in 1999, led by Eve Van Cauter, a professor of medicine at the University of Chicago, showed that just six days of sleep restricted to four hours pushed 11 healthy young male volunteers into a pre-diabetic state. Those jaw-dropping results expanded the field of sleep research, and convinced scientists that chronic, partial sleep deprivation damaged the body, not just the mind.