People who sleep less than six hours per night or more than eight are more likely to suffer heart problems than people who sleep between six and eight hours, said a US study on Sunday.

The findings confirm those in previous, smaller studies, but are based on what researchers described as a nationally representative sample of 3,000 people covering five separate heart ailments and their links to sleep duration.

The subjects for the study were people over age 45 who participated in a survey of health issues in US households known as the National Health and Nutrition Examination Survey.

Subjects were asked to describe their sleep patterns and were also asked if they were ever told they had congestive heart failure, heart attack, coronary artery disease, angina or stroke.

People who said they got too little sleep each night were two times more likely to have a stroke or heart attack and 1.6 more likely to have congestive heart failure than people who slept between six and eight hours nightly, the researchers said.

People who said they slept more than eight hours per night were two times more likely to have angina and 1.1 times more likely to have coronary artery disease.

"We now have an indication that sleep can impact heart health, and it should be a priority," said principal investigator Rohit Arora, chairman of cardiology and professor of medicine, the Chicago Medical School.

"Based on these findings, it seems getting six to eight hours of sleep everyday probably confers the least risk for cardiovascular disease over the long term." (AFP)