London, April 22 (IANS): Those who doze off during the day to catch some 'missed' night sleep, beware!

According to an alarming research, middle-age and older adults who take daytime naps at office or home may be at increased risk of dying.

In particular, naps were linked with an increased risk of dying from respiratory diseases.

Those between ages 40 and 65 were nearly twice as likely to die during the study period if they napped for an hour or more, compared to those who did not nap, the researchers from University of Cambridge said.

“Excessive daytime napping might be a useful marker of underlying health risks, particularly respiratory problems, especially among those 65 years of age or younger,” emphasised Cambridge epidemiologist Yue Leng and lead author of the study.

It may not be napping per se that is unhealthy, but rather, that those who tend to nap also have undiagnosed medical conditions that affect their risk of dying, the researchers noted.

The study involved more than 16,000 people in Britain who answered questions about their napping habits between 1998 and 2000, and were followed for 13 years.

People aged 40 to 79 who napped daily, for less than an hour, were 14 percent more likely to die over a 13-year period, compared to those who did not nap.

People whose daily naps lasted an hour or more were 32 percent more likely to die over the study period, the research, published in the American Journal of Epidemiology, added.

The researchers took into account many factors that could affect people's risk of death, such as their age, gender, body mass index (BMI), smoking, exercise, and whether they had certain pre-existing medical conditions such as diabetes, cancer or asthma.

"Further studies are needed before any recommendations can be made," the researchers concluded.