If you like taking an afternoon power nap as a way to recharge, make sure it’s a short one.
According to the results of a recent study, those who napped for more than half an hour per session had a higher risk of developing type 2 diabetes than those who took either a shorter nap or no nap at all.
The study focused on 27,000 people in China-where afternoon napping is extremely popular-and found that those who napped longer than 30 minutes were also more likely to develop high blood pressure and hypertension.
Conducted by researchers from the Huazhong University of Science and Technology in China, the study looked at 27,009 men and women aged 45 or over, and used an impaired fasting plasma glucose test to determine whether or not their blood sugar levels were too high and if they were at risk of developing diabetes.
Almost 70 percent of those studied said they regularly took an afternoon nap, and those nappers tended to show much higher glucose levels than those who did not revisit their childhoods with an afternoon siesta.
Almost half of them, about 40 percent, also had high blood pressure, compared to 33 percent of those who did not pause for an afternoon snooze.
Researchers suggested that napping could be detrimental because it not only reduces time available for exercise, but may also disrupt the body’s internal clock, resulting in higher levels of the damaging stress hormone cortisol.
“Napping in the elderly can be beneficial for daytime functioning, as well as for mental health,” researchers said, “but there is accumulating evidence showing it may also be a risk factor for morbidity and mortality.”
The research appeared in the journal Sleep Medicine, and echoes the results of a previous study linking naps and diabetes.
In 2010, researchers tracked almost 20,000 Chinese participants (men and women aged 50 and over, and found that those who napped frequently were 42 to 52 percent more likely to have diabetes.