Impacts on Metabolism and Endocrine Function
Studies by Spiegel, Van Cauter, and colleagues 9,10 linked sleep loss with insulin resistance, changes in hormones that increase hunger and appetite, and increases in evening cortisol levels.
In the studies, young, healthy men restricted their sleep to 4 hours a night for 6 nights. At the end of this time, their test results showed clinically diagnosable impairment of glucose tolerance. These findings have received a lot of scientific attention and suggest that not only do sleep-deprived people feel sleepy but also other changes occur in their bodies. The scientific sleep community warns growing scientific evidence links inadequate or mistimed sleep to molecular, immune, and neural changes that play a role in the development of a broad range of chronic health problems such as obesity, diabetes, and cardiovascular disease.3,11,12
If you wish to learn more after this training program, see the link in Other Resources for interviews with Van Cauter and other scientists who discuss these findings.