Naomi Kresge / Bloomberg News

BERLIN — Tour de France cyclists outlived ordinary men by six years in a study that suggests the strain of intense workouts may not be so bad for the heart after all.

The study examined 786 French cyclists who had taken part at least once, between 1947 and 2012, in the grueling bicycle race that has been compared to climbing Mt. Everest three times or running a marathon for three weeks.

Researchers compared the cyclists with the rest of the population of French men the same age. About a quarter of the riders had died by Sept. 1, 2012 — a mortality rate 41 percent lower than in the control group, said Xavier Jouven of the Sudden Death Expertise Center in Paris. Jouven said the cyclists’ comparative longevity surprised him and his colleagues.

“We expected to observe exactly the opposite,” Jouven said this week in a webcast press conference from the European Society of Cardiology’s annual meeting in Amsterdam. Doctors should think twice before warning people who aren’t high-risk patients away from intense sports, he said. “We have to encourage people to exert themselves.”

The study results come amid debate about how much exercise is too much, especially for middle-aged men pushing themselves through endurance races such as triathlons.

The cyclists in the study were hardly weekend warriors. The elite athletes probably maintained a habit of rigorous exercise over many years, according to Jouven.

The death rate statistic held true for all age groups except those younger than 30. The younger racers showed a trend toward dying sooner than the general population. Traffic accidents accounted for much of the mortality in that group, compared with heart disease and tumors for the older athletes, the researchers said.