(CNN) — 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.
Previous research supports the idea that endurance exercise carries a risk. A 2012 study from the Mayo Clinic found that excessive training can cause cardiovascular damage such as scarring and enlargement of the heart and blood vessels.
“You can do light to moderate exercise as long as you want. We’re genetically designed for that kind of activity,” Dr. James O’Keefe, a cardiologist at the Mid America Heart Institute, told CNN at the time. “We’re just not designed to run 26 miles at a time, or 100, or go on a full-distance triathlon for 12 hours as hard as you can go.”
The Centers for Disease Control and Prevention recommends adults get two hours and 30 minutes of moderate-intensity aerobic activity every week or one hour and 15 minutes of vigorous aerobic activity a week (i.e., running). You should also strength train two or more days a week.
Marriage is good for your heart — and other findings from the ACC conference