Losing sleep doesn't just make us hazy and irritable. It can also lead to cardiovascular disease, type 2 diabetes, and a host of other conditions. But catching up on some shuteye may help combat these problems. According to a new study, sleep-deprived men who dozed an extra 2 to 3 hours on the weekend may reduce their risk of developing type 2 diabetes.
Researchers led by Peter Liu, an endocrinologist at the Los Angeles Biomedical Research Institute at the Harbor-University of California, Los Angeles, Medical Center, recruited 19 men in good health who, due to their workload, were poor sleepers. The subjects, age 29 on average, had been clocking about 6 hours of shuteye on weeknights for just over 5 years. However, they made the most of their weekends and slept an extra 2.3 hours a night on Friday and Saturday. When selecting the candidates for the trial, the scientists verified their reported schedules using sleep actigraphs, devices worn like wrist watches that record sleep patterns.
The men slept in the lab for three nights. Some were allowed to sleep 10 hours without interruption, catching up on the sleep that they had lost earlier in the week. Others slept 10 hours with frequent interruption, and still others slept 6 hours without interruption. All the subjects ate the same diet, so the researchers could normalize their insulin and sugar levels.
On the 4th day, the team took blood samples from the men and calculated their sensitivity to insulin, the hormone that helps regulate blood sugar; low sensitivity is a precursor to type 2 diabetes. The researchers also calculated the men's HOMA-B score, which indicates the level of insulin resistance—a condition that prevents cells from responding to the hormone making glucose. The HOMA index also measures the function of the body's β cells—the workhorses of the pancreas that store and release insulin.
Overall, men who got catch-up sleep (10 hours) showed a 31% increase in insulin sensitivity over the subjects who slept only 6 hours per night, Liu and colleagues report today at the annual meeting of The Endocrine Society in San Francisco, California. Their insulin resistance also decreased. "The good news is that by extending the hours they sleep, adult men—who over a long period of time do not get enough sleep during the working week—can still improve their insulin sensitivity," Liu said.
The study suggests a new way to combat type 2 diabetes, which is the seventh highest cause of death in the United States, says Hans Van Dongen, head of the Human Sleep and Cognition Laboratory at Washington State University, Spokane. "Liu's work provides yet another good reason to challenge the stigma associated with 'sleeping in' and recognize that catching up on sleep when given the chance may be a good thing."