No, this isn’t an excuse to put down your running shoes. Unless, of course, you’re already running more than 20 miles a week.

Research presented this week at the annual American College of Cardiology Scientific Sessions in Washington shows runners who average more than 20 miles a week don’t live as long as those who run less than 20 miles a week. In fact, they live, on average, about as long as people who don’t run much at all.

In other words, like most things in life, moderation may be key.

The study authors analyzed data from more than 3,800 men and women older than 35 who are participating in the Masters Running Study. Participants reported their weekly running averages as well as information about their cardiovascular health and use of common painkillers such as aspirin and ibuprofen. Nearly 70% of the study participants reported running more than 20 miles a week.

Researchers saw a U-shaped data set when they looked at longevity compared with the runners’ mileage. Those who ran a moderate amount each week tended to live the longest.

The study authors could not find a strong association between cardiovascular health or painkiller use and the long-distance runners’ shorter life spans, so the reason behind this link remains unclear.