The researchers zeroed in on 8,600 of the participants who had been part of the study for about 25 years.

They cross-referenced records with the national death registry to see if and when any of these people had passed away.

Then they compared activities and life spans.

The most obvious finding was that people who had reported almost never exercising were more likely than the active to have died in the ensuing decades.

The associations between particular activities and life span were more surprising.

Cycling was the most popular activity among the Danes in the study, many of whom reported riding for four or more hours every week. Their pedaling was associated with a lengthier life span, adding an average of 3.7 years to riders’ lives, compared to sedentary Danes.

Running likewise was associated with an extra 3.2 years of life.

But these gains were notably less than for playing tennis, which was linked to 9.7 added years of life, or badminton, which was linked to an extra 6.2 years, or soccer, which added almost 5 years to players’ lives.

These associations remained unchanged even when the researchers controlled for people’s education, socioeconomic status and age.

Why and how some sports might add more years to people’s lives than others is impossible to know from this kind of observational study, says Dr. James O’Keefe, a study co-author and the director of preventive cardiology at the Mid America Heart Institute at Saint Luke’s Health Center in Kansas City.