Overtime work might be bad for your heart, study concludes

Working 10 hours or more a day may harm the heart, according to a study of more than 10,000 British civil servants.

People who added three or more hours to a seven-hour day had a 60 percent greater risk of heart attack, angina and death from cardiovascular disease than those with no overtime work, researchers from Britain, Finland and France reported in the European Heart Journal. The findings are from the Whitehall II study, which has tracked British civil servants since 1985.

The results bolster evidence that suggests working overtime is linked to poor health and may play a greater role in heart disease than previously thought, wrote Gordon McInnes, a professor of clinical pharmacology at the University of Glasgow, in an editorial accompanying the study. Physicians should consider working hours when patients experience chest pain or show symptoms of heart disease, he said.

"Employees with the highest risk of coronary heart disease claimed to work 11 to 12 hours per day, a most unusual work pattern certainly in the European context," McInnes wrote. "Overtime-induced work stress might contribute to a substantial proportion of cardiovascular disease."

About 10 percent of the civil servants tracked worked three or four extra hours a day. Those workers tended to have an aggressive and competitive pattern of behavior, signs of psychological distress, and possibly a lack of sleep, said the researchers, led by Marianna Virtanen of the Finnish Institute of Occupational Health in Helsinki.

Over the 11 years studied, the researchers found 369 cases of fatal coronary heart disease, heart attacks that weren't lethal, and angina, a severe chest pain caused by the narrowing of the arteries that supply the heart muscle. Additional studies are needed to explain the link between overtime and heart health, they said.