Pull your head out from under the covers: Taking long naps might increase your risk of heart problems and diabetes, a new meta-analysis presented at the American College of Cardiology’s (ACC) Annual Scientific Session suggests.
After analyzing data on more than 300,000 people from 21 different studies, the researchers concluded that people who napped more than 60 minutes a day—and who reported high levels of daytime fatigue—were about 50 percent more likely to develop diabetes than those who napped for less than an hour a day.
The combo of hour-plus naps and daytime tiredness also spiked the risk of developing metabolic syndrome—a constellation of factors linked to heart disease, like a large waistline, high blood pressure, and high levels of triglycerides—by about 50 percent, too.
But the study didn’t show cause and effect, so the researchers can’t say for sure whether the long naps was actually responsible for the increased risk of those conditions.
In fact, it might be that your need to take long naps is signaling something might not be quite right with your body, says ACC member Peter Farrehi, M.D., assistant professor of medicine at the University of Michigan.
One possible reason? Feeling excessively tired during the day could mean you have undiagnosed obstructive sleep apnea, a condition where you stop breathing during sleep, he says.
That means you don’t receive enough oxygen while you’re snoozing, so your body continuously wakes yourself up to get air.
As a result of your poor, fragmented sleep, the sleep center in your brain releases excess stress hormones like cortisol.
Too much cortisol can raise your blood pressure, increasing your chances of developing metabolic syndrome, Dr. Farrehi says.
Past research also suggests that cortisol can also spike your blood sugar levels, a known risk for type 2 diabetes.
Your move: Shoot for at least 7 hours of quality sleep each night, Dr. Farrehi recommends.
If you’re still feeling exhausted even after snoozing that long, that’s your cue to talk to your doctor: He or she may want to evaluate you for breathing disorders or order blood work to check for fatigue-causing conditions like anemia.
As for the occasional long nap? It’s not easy to say whether one long nap is safer than daily ones, says Dr. Farrehi. But if you’ve been short on sleep all week, listen to your body and rest up.
Even better: Keep your nap to less than 30 minutes.
In the study, these shorter naps weren’t linked to any increased chances of metabolic syndrome or diabetes—and awakening after 30 minutes is less likely to leave you groggy, too.