It seems that working hard can, in fact, kill you. A new study shows a strong correlation between long working hours and two major health problems: Cardiovascular disease and strokes.

The study, conducted by Mika Kivimaki, a professor of epidemiology at University College London, tracked 600,000 adults in the United States, Europe and Australia over a period of eight years. While Kivimaki does not claim to have proven that hard work is a direct cause of the health problems, but the correlation between the two was significant. Those who worked 55 hours a week or more were 13 percent more likely to suffer from heart disease than those who worked standard hours. 

A separate analysis of 17 similar studies that tracked over 500,000 adults concluded that those working over 55 hours a week were one-third more likely to suffer from heart disease. Workers who put in 41 to 48 hours a week were 10 percent more likely to develop heart disease, while those who worked 49 to 54 hours a week were 27 percent more likely.