Vitality

Long Naps, Excessive Daytime Sleepiness May Increase Risk For Metabolic Syndrome

napping
Napping for more than 40 minutes is associated with a greater risk of metabolic syndrome, study finds. CARL COURT/AFP/Getty Images

Who doesn't love naps? Besides kindergarteners and workaholics, but this is not about them. Not only are naps blissful, they are also perfect when you need a boost in alertness and energy. In addition to recharging your body and mind, naps can help you reduce stress, retain information and ease frustration. But new research presented at the American College of Cardiology's 65th Annual Scientific Session shows that you can have too much of a good thing, even naps.

Researchers at the University of Tokyo found that napping for 40 minutes or longer was associated with an increased risk of developing high blood pressure, high cholesterol, high blood sugar and excess fat around the middle — which all fall under the umbrella term metabolic syndrome, a cluster of conditions associated with an increased risk for developing heart disease. Daytime sleepiness was also tied to greater risk of metabolic syndrome.

The study builds on previous work done by the same group that links long naps and excessive daytime sleepiness to type 2 diabetes. Meanwhile, The National Sleep Foundation recommends short naps that are 20 to 30 minutes long for improved alertness and performance.

"Sleep is an important component of our healthy lifestyle, as well as diet and exercise," Dr. Tomohide Yamada, lead author of the study, said in a statement. "Short naps might have a beneficial effect on our health, but we don't yet know the strength of that effect or the mechanism by which it works."

Yamada and her team came up with these findings after combing through 21 observational studies involving more than 300,000 Asian and Western subjects. They compared the participants answers to questions assessing their daytime sleepiness to their metabolic syndrome, type 2 diabetes, and obesity.

Quick shut-eye that lasts less than 40 minutes did not show an increased risk for metabolic syndrome. However, the risk for developing a cluster of heart disease risk factors rose sharply if people napped beyond 40 minutes. In fact, people had a 50 percent increased risk of developing metabolic syndrome if they napped for 3 hours. Interestingly, researchers noticed a lower risk of  developing metabolic syndrome if they napped less than 30 minutes.

Napping for 90 minutes appeared to increase risk by as much as 50 percent, as did being excessively tired during the day. And again, there was a slight dip or decrease in the risk of metabolic syndrome among those napping less than 30 minutes.

"Taking naps is widely prevalent around the world," Yamada said. "So, clarifying the relationship between naps and metabolic disease might offer a new strategy of treatment, especially as metabolic disease has been increasing steadily all over the world."

While previous studies have linked midday naps to early death and an increased dementia risk, others have linked them to many health benefits, including reduced heart attack risk and lower blood pressure.

Source: American College of Cardiology's 65th Annual Scientific Session. 2016.

Loading...