The Newly Discovered Health Benefit of Sleeping In on Weekends

Not getting enough sleep can do a real number on your health. And when that lack of sleep becomes chronic, it introduces all sorts of risks, including a higher chance of developing cancer, type 2 diabetes, metabolic disease, and heart problems. Your genetic health and sleep are even closely related. "When your sleep suffers, you suffer major consequences beyond the dark circles under your eyes. Your level of cortisol, a key stress hormone, is higher—and that makes you eat more and store belly fat," says Shawn Stevenson, author of Sleep Smarter. "Your thyroid slows down. Insulin doesn't work as well, and your blood sugar gets out of whack."

"Studies have shown that just one night of sleep deprivation can make you as insulin resistant as a person with type 2 diabetes," Stevenson says. "This translates directly to aging faster, decreased libido, and storing more body fat than you want to. Now stretch that out over weeks, months, even years, and you can start to see why lack of sleep can be such a huge problem."

In fact, even short-term sleep restriction, with four or five hours of sleep per night, can increase the risk of developing diabetes by about 16 percent—comparable to the increase in risk caused by obesity.

But a promising, although small, study suggests that using the weekend to catch up on sleep lost earlier in the week could help reverse some of the damage done, at least in terms of type 2 diabetes. Researchers at the University of Chicago sleep lab studied 19 healthy young men to investigate the metabolic effects of different sleeping patterns. For four nights, the men only got about 4 hours and 20 minutes of sleep a night. Then, for the next two days, they were allowed to sleep in as long as they wanted, which wound up being close to 10 hours each night. During the span of less sleep, the men's insulin sensitivity fell 23 percent (that's not good, as a lack of insulin sensitivity can set you up for type 2 diabetes over time); their risk of diabetes rose 16 percent. Interestingly, the insulin sensitivity and diabetes risk readings returned to normal levels after the two-day sleep-in period.

"In this short-term study, we found that two long nights spent catching up on lost sleep can reverse the negative metabolic effects of four consecutive nights of restricted sleep," says study author Josiane Broussard, PhD, now an assistant research professor in the Department of Integrative Physiology at the University of Colorado, Boulder.

While this evidence that catch-up sleep is beneficial is exciting, especially for those of us who work long work-week hours, the study authors caution that larger studies are needed. They also warn that they only looked at one week of sleep, and that people living in a chronic state of sleep deprivation may not be able to reverse the health damage by sleeping in on weekends.