ANNOUNCER: In other words, studies have shown some potentially serious physical consequences can arise as a result of chronic sleep loss.
EVE VAN CAUTER, PhD: Sleep loss has an adverse effect on our ability to metabolize sugar. In one week of severe sleep deprivation, such as four hours per night, a healthy, lean, fit volunteer will be in a pre-diabetic state.
With sleep loss, we have also noticed an increase in hunger and appetite and profound alterations in hormones that regulate hunger and appetite. Such that, when you're sleep-deprived, you may overeat well in excess of the caloric demands, and, therefore, sleep loss is probably also a risk factor for weight gain and obesity.
ANNOUNCER: Lack of sleep can set off a variety of hormonal changes, affecting our mood and even our growth.
EVE VAN CAUTER, PhD: Cortisol, which is a stress hormone, and normally cortisol is very low in the evening, because it sort of prepares us for a relaxed state to go to sleep. But in a state of sleep debt, cortisol levels in the evening are elevated. So somehow, a state of sleep loss is read as a stressor.
ELLEN MILLER, MD: As young girls and boys enter puberty, they have pulsations of different hormones from their brain that put them into puberty. And these pulsations occur at night while they're sleeping. So if they are not on a normal sleep-wake cycle, this can interfere with the pulsatile secretion of these hormones and it can affect when and how they go through puberty. And with going through puberty, affects their height and their growth.