It’s been said that too much exercise can be harmful to our health, but researchers have now found that people who can run a mile in under 4 minutes generally live several years longer than expected.

Regular exercise is important for heart health, but too much strenuous activity has been linked to harmful heart outcomes.

“During periods of intense or prolonged endurance exercise such as running or cycling, certain proteins are released that indicate possible heart injury,” says Stephen Foulkes of the University of Alberta in Canada.

To learn more about the effects of exercise, Foulkes and his colleagues looked at the ages of the first 200 athletes recorded running a mile (1.6 kilometers) in less than 4 minutes.

All athletes were men born between 1928 and 1955. Among them was British neurologist and athlete Roger Bannister, the first person in the world to be recorded running a distance of less than 4 minutes, 70 years ago.

60 of the contestants have died by December 2023, with an average age of 73 years. The surviving contestants were 77 years old, on average.

When accounting for where and when each athlete was born, the team calculated that runners under 4 minutes lived on average 4.7 years longer than the general population.

Specifically, those who ran their first sub-4-minute mile in the 1950s lived more than nine years longer than the general population, while those who achieved the feat in the 1960s and 1970s lived 5.5 and 3 years longer, respectively.

This may be because the general population has become healthier over time, says team member Mark Haikoski, who also works at the University of Alberta.

The results suggest that excessive exercise may not be as harmful as previously thought. “These athletes build a highly capable system in their hearts, lungs, blood vessels, muscles, and immune systems that may enable them to recover well from the stresses of normal daily life,” Foulkes says.

But Theis Eijsvogels of Radboud University in the Netherlands says these findings alone do not challenge the “excessive exercise hypothesis” — the idea that long-term, high-intensity exercise can have negative effects on the heart.

“They tested whether ultra-fit individuals had different mortality risks compared to the general population,” he says, but it’s possible that people with less extreme exercise regimens have different or even better outcomes.