Making Up for Lost Sleep

Plenty of us don’t get enough sleep. A 2016 study by the CDC found that 35% of adults, or about 1 in 3, aren’t getting the recommended 7 hours of sleep each night. Over the last 40 years, studies estimate that the number of young adults who sleep less than 7 hours a night has more than doubled. And sleep experts say that’s a big problem.

Burning the midnight oil doesn’t just make you bleary-eyed and brain-fogged the next day, it can also take a toll on your metabolism. Studies have shown that getting less than 6 hours of sleep a night reduces the body’s ability to efficiently regulate blood sugar, increasing the odds of obesity and diabetes. Too little sleep is also associated with high blood pressure, heart disease, decreased sex drive, accidents, and an increased chance of early death.

But a rough night or two, or a weeklong sleep deficit, doesn’t necessarily doom your health. Recent studies have shown that you can undo at least some of the damage by catching up -- either by sleeping longer on weekends or setting and following a reasonable goal to get a little more sleep. One 2015 study found that men and women who averaged about 6 1/2 hours of sleep a night improved their insulin resistance and fasting blood sugar by just sleeping an extra hour each day, bringing their nighty total to around 7 1/2 hours.

Another recent study took 19 healthy young men and slashed their sleep to about 4 hours a night for 4 nights. Researchers took blood samples and, to no surprise, found their sensitivity to the hormone insulin had dropped by about 23%, indicating they were on the road to diabetes.

After their sleep-deprived days, however, the men were allowed 2 days of catch-up sleep, where they averaged about 10 hours in bed. After the extra sleep, their insulin and blood sugar levels returned to normal, suggesting the damage had been undone.

“With sleep deprivation, as many, many other studies have shown, there was a reduction in insulin sensitivity and increased diabetes risk. The levels appeared to return, at least statistically, to the normal sleep levels after we did the catch-up sleep,” says study author Esra Tasali, MD, director of the Sleep Research Center at the University of Chicago in Illinois.

“I don’t want people to think this replaces the healthy sleep recommendation of 7 to 8 hours a night. But on occasion, if your situation doesn’t allow you to extend your sleep on weekdays, this could be an alternative,” she says.