LONDON - Working long hours and getting little sleep or time off is a sure-fire shortcut to an early grave, according to a new Anglo-Japanese study.
"Working 60 or more hours a week, and regularly not getting much sleep, may double the risk of having a heart attack," said the study, published recently in the journal Occupational and Environmental Medicine.
"An average night's sleep of five or fewer hours, for two nights of the working week, was associated with a doubling and even tripling of the risk," it added.
The study, conducted between 1996 and 1998, looked at 260 men aged between 40 and 79 who had survived a first heart attack and matched them against 445 comparable men with no history of cardiac arrest.
All were questioned closely about their work, relaxation and sleep patterns as well as other key areas such as lifestyle, weight, diet, blood pressure, cholesterol and diabetes.
The study found that while all participants had similar lifestyles and medical conditions, the heart attack group worked far longer hours, hardly relaxed and slept less than five hours a night significantly more often than the other group.
The authors, Suminori Kono of Kyushu University in Japan and David Snashall of Guy's and St Thomas's NHS Trust in London, said sleep deprivation led to raised blood pressure while chronic stress caused heart function abnormalities.
Both of these were potential triggers for a heart attack.
The authors concluded that the optimal working week was a maximum 40 hours, and advised those working longer to get more sleep and take longer breaks. (Agencies via Xinhua)