Dr. Plamen Penev, of the University of Chicago, Illinois, and a senior author of the study and colleagues subjected 11 healthy but sedentary middle-aged men and women to two 14-day periods of sedentary living with free access to food and either 5.5 hours or 8.5 hours of sleep each night.
As nightly sleep times changed from 8.5 to 5.5 hours, the participants went to bed later and got out of bed earlier and, as a result, average sleep duration was reduced by about two hours a day.
When the adults had their bedtimes decreased from a healthy 8.5 hours to 5.5 hours they showed changes in their response to two common sugar tests, which were similar to those seen in people with an increased risk of developing diabetes.
During sleep, your body removes the buildup of waste in the brain. Sufficient sleep is necessary for the normal function of your nervous and endocrine systems. Most civilizations in human history recognized the value of mid-afternoon naps. The desire for a rest, short sleep, or “siesta” after lunch should not be seen as an abnormal need, but rather a normal one. People who “cover up” their lack of sleep by using drugs (such as caffeine) as food and/or food (such as highly processed, sugary foods) as drugs sometimes claim (even boast) that they can get by with very little sleep. As you begin to live more healthfully, you may quickly recognize that you need more sleep than you previously thought.