SLEEPING for between six and eight hours a night could be key to cutting the risk of heart problems and stroke, researchers claim.
A study found people who sleep for fewer than six hours a night were twice as likely to suffer a heart attack or stroke as those who sleep for between six and eight hours.
They also had a two-thirds higher risk of congestive heart failure, where the heart's ability to pump blood around the body weakens, damaging other organs.
But sleeping for more than eight hours was associated with more than double the risk of angina and a 19 per cent higher likelihood of coronary artery disease.
Author Dr Saurabh Aggarwal, of Chicago Medical School, said six to eight hours was the "best period of sleep duration", adding: "People whose sleep duration is at the extremes are at the highest risk of cardiovascular events."