10-hour work days may harm heart, study says

LONDON - 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 yesterday in European Heart Journal. The findings are from the Whitehall II study, which 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.

"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."

Of the civil servants tracked, about 10 percent 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, the researchers said.