A new study, published in the Journal of the American College of Cardiology, shows that running too much can be just as unhealthy as not being active at all. People who push their bodies too hard may essentially undo the benefit of exercise.

According to the study, those who ran at a fast pace more than four hours a week for more than three days a week had about the same risk of dying during the study’s 12-year follow up as those who were sedentary and hardly exercised at all.

In fact, those with the lowest risk of dying during the study period were people who ran less than three times a week for one to 2.4 hours, at a slow to moderate pace. Even people who ran slightly more, for 2.5 hours to four hours a week at an average pace less than three times a week, showed slightly higher mortality risk, at 66%.

Here’s how I would conclude this study: keep doing your exercise, but do it in moderate amounts and intensity, and make sure you have days where you rest. Too much of something is usually not good.