Over a 12-year study period, people who worked 11 hours or more a day were far more likely to develop heart trouble compared with those who worked seven to eight hours a day.
In fact, those working ten hours a day were not at more risk. However, workers who put in 11 or more hours a day were 66 percent more likely to have a heart attack or die of one.
Those who had reported working 10 or more hours a day were not at significantly greater risk than those who had worked less. But those subjects who had been working 11 or more hours a day were 66 percent more likely to have a heart attack or to die of one, the researchers found.
The author of the study said it was not clear whether working long days were causing the heart problems or were simply a number that could be used to predict them. He said, the chronic experience of stress and working long hours may affect the body, or it may lead to depression and sleep problems.