A good reason to go to bed early tonight

Researchers from Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center found that insulin sensitivity, the body's ability to clear glucose (blood sugar) from the bloodstream, significantly improved after three nights of "catch-up sleep" in men with long-term, weekday sleep restrictions.

"We all know we need to get adequate sleep, but that is often impossible because of work demands and busy lifestyles," said lead researcher Dr. Peter Liu, MD, PhD. "Our study found extending the hours of sleep can improve the body's use of insulin, thereby reducing the risk of Type 2 diabetes in adult men."

Liu and researchers from the University of Sydney in Australia studied 19 healthy men who didn’t have diabetes but who reported chronically coming up short on sleep during the workweek.

Subjects reported, on average, about six hours of sleep each work night, while catching up on their sleep during the weekends, sleeping an extra 2.3 hours per night. Their sleep times were verified by actigraphy, in which each man wore a small device on his wrist that monitored sleep-wake cycles.

The men spent three nights in a sleep lab on each of two separate weekends. The researchers randomly assigned the men to two of three sleep conditions: (1) 10 hours of sleep, (2) six hours of sleep or (3) 10 hours in bed, in which noises during deep sleep aroused them into shallow sleep without waking them.

On the fourth morning, the research staff drew the men's blood to measure their blood sugar and insulin levels to calculate insulin sensitivity. Subjects ate the same meals during the study visits, so that diet would not influence the results, Liu said.

When the men slept 10 hours a night on each of three nights of catch-up sleep, their insulin sensitivity was much better than when they had persistent sleep restriction, the scientists found. Their insulin resistance test score also improved with the extra sleep.