WORKING more than 40 hours a week increases the chances of having a heart attack, according to a study published today.
Men who worked more than 60 hours a week were twice as likely to suffer a heart attack as those on 40-hour weeks, researchers found.
The risk tripled for men who had less than five hours' sleep a night for at least two days in the working week. Researchers said the results were so significant that people should work no more than 40 hours a week and have at least two weekdays off a month to reduce the chances of heart disease.
Experts said findings from the study, published in the journal Occupational and Environmental Medicine, had major implications for Britain, where people work the longest hours and have the fewest holidays
in Europe. Heart disease is the UK's biggest killer, claiming the lives of one in four men and one in five women. More than 270,000 people each year suffer a heart attack, and half of them die.
Researchers in Japan studied the lives of 260 men between the ages of 40 and 79 who had suffered a first heart attack, and compared them to 445 men of a similar age with no history of heart disease. They found that the heart attack victims were significantly more likely to have been working longer hours, having fewer days off and less sleep than the healthy men.
Study author Dr Suminori Kono, from Kyushu University in Japan, said: "These findings suggest that chronic overwork and sleep deprivation confer an increased risk of [heart attack]." Previous studies have found that overtime work can increase blood pressure and heart rate and cause chest pain, depression and fatigue.
Lack of sleep can also lead to a rise in blood pressure and heart abnormalities which can cause cardiac arrest.
British employees work an average 43.5 hours a week - three hours more than the rest of Europe. We work 8.7 hours a day, compared to French workers on 7.9 hours, Germans on eight and Italians on 7.7 hours.
But many workers here say they put in far more hours a week when overtime, weekend working and other duties are counted.
UK workers have 28 days' annual holiday while the French have 47, the Germans 41 and the Spanish 46.
Dr David Snashall, an occupational health expert at Guy's Hospital, said: "This is an important study which raises serious concerns about the part work and lack of sleep can play in triggering heart attacks.
"Long working hours are bad for people socially and have safety implications for people such as doctors and train drivers, where the lack of sleep can sometimes lead to tragic accidents. There is clearly evidence here that pushing people hard at work can trigger coronary heart disease. We now need more research."