One hundred years ago, adults in the United States averaged 9 hours of sleep per night. Today, that average is less than 7 hours. Although researchers have shown that lack of sleep can impair mental function, they have yet to demonstrate any physical consequences of sleep deprivation.
A study from the University of Chicago now suggests the body's reaction to sleep loss resembles insulin resistance, a condition in which cells fail to efficiently use this sugar-processing hormone. Insulin resistance results in high blood-glucose concentrations and can lead to type II, or adult-onset, diabetes.
The researchers recruited 13 people chronically short of sleep, averaging less than 6.5 hours per night, and 14 other people who typically snoozed more than 7.5 hours nightly. The groups had matching ethnicity and medical histories.
For 8 days, participants wore a wrist device that monitored nighttime movement, which diminishes when people are asleep. They also kept a sleep di