Napping once or twice a week could be the secret to a healthy heart, scientists have found.

A new study showed people who enjoyed a small number of daytime naps a week were at nearly half the risk of life-threatening events such as heart attack or stroke.

The effects of napping is one of the least studied areas in the field of sleep, however researchers believe the practice may benefit cardiovascular health because it relieves stress.

A team at University Hospital Lausanne in Switzerland studied data on 3,262 people aged between 35 and 75 who were monitored for an average of five years.

Those who napped once or twice in seven days, for between roughly five and 60 minutes, were 48 per cent less likely to suffer a heart attack, stroke or heart failure compared to those who did not nap at all.

However, the more frequently people napped beyond this level the more likely they were to suffer a serious heart event.

This is because the tendency to nap frequently may itself be a result of underlying health problems, the researchers said.

The beneficial effect of napping once or twice weekly on CVD remained even after controlling for major cardiovascular risk factors, such as smoking.