Catching 40 winks in the middle of the day may get you the sack, but will protect you from a heart attack.
A large UK study of 23,681 people in Greece reported that those who cat-napped for at least 30 minutes in the afternoon, three times or more a week had a 37 per cent lower risk of death due to heart attacks compared to those who did not.
People who occasionally took a siesta had a 12 per cent lower risk. In the study, a siesta was defined as "typically short naps or rest periods of no more than an hour that are taken in the afternoon".
Cardiologists say siestas help people relax, reduce their stress levels and benefit heart function by lowering blood pressure. "Blood pressure and heart rate decrease while sleeping. Lowered blood pressure reduces strain on the heart and decreases the risk of a fatal heart attack," says Dr RR Kasliwal, senior consultant cardiologist, Apollo Hospital.
Dr Kasliwal, however, cautioned that afternoon naps should not lead to reduced overall physical activity. "Taking a long afternoon nap can lead to heightened heart risk by making people inactive and overweight," says Dr Kasliwal. The World Health Organisation recommends people engage in moderate physical activity for 30-40 minutes a day for optimal heart health.
Most studies in the past have focused on nighttime sleeping. This study provides a detailed description of changes in heart function of daytime sleep in healthy individuals, comparing napping with other daytime activities such as standing and lying down without going to sleep. The UK study — published in the online edition of the Journal of Applied Physiology — found that beneficial cardiovascular changes take place even before a person falls asleep.
A significant drop in blood pressure was recorded among volunteers mostly after lights out, or just before they fell asleep.