NEW YORK - An inadequate amount of nightly sleep on a recurring basis, coupled with a sedentary lifestyle and overeating, may fuel the development of diabetes, results of a new study hint.

"Our findings suggest that combining the unhealthy aspects of the Westernized lifestyle with insufficient sleep may add to the risk of overweight and sedentary individuals to develop diabetes," Dr. Plamen Penev, of the University of Chicago, Illinois, and a senior author of the study, told Reuters Health.

Penev 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.

"If confirmed by future larger studies," Penev told Reuters Health, "these results would indicate that a healthy lifestyle should include not only healthy eating habits and adequate amounts of physical activity, but also obtaining a sufficient amount of sleep."

SOURCE: Journal of Clinical Endocrinology and Metabolism, September 2009.