A new British study says working too much over-time could be bad for your health.

Researchers followed about 6,000 people for 13 years. Doctors found that people working 10 hours a day were 60 percent more likely to have heart problems, including death due to heart disease, non-fatal heart attacks and angina.

The study found though that people working only 8 or 9 hours a day had no significant increase in heart problems.

In an accompanying editorial, Dr. Gordon McInnes, M.D., of the University of Glasgow pointed to overtime work stress as a contributor to heart problems. But "further research should examine whether interventions designed to reduce overtime work could alter the risk of cardiovascular disease," he wrote.