If you're putting too much heart into your work, you could end up with heart disease -- at least if your love of the job leads to too many hours on the clock. A British study found employees who worked three to four more hours of overtime a day were 60% more likely to develop heart disease than those who clocked in at a normal seven-hour British work day. The study was conducted over an 11-year period and included research from 6,000 civil servants.

Among the study group, there were a reported 369 cases of death due to heart disease, non-fatal heart attacks and angina. From Reuters:

"It seems there might a threshold, so it is not so bad if you work another hour or so more than usual," said Dr Marianna Virtanen, an epidemiologist at the Finnish Institute of Occupational Health and University College London. The higher incidence of heart problems among those working overtime was independent of a range of other risk factors including smoking, being overweight or having high cholesterol.

One group likely very high at risk? Pilots.