Interplay of factors

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, said Dr. James O’Keefe, a study co-author and the director of preventive cardiology at the Mid America Heart Institute at St. Luke’s Health Centre in Kansas City, Missouri.

The differing physical demands of some sports could play a role, he said, although little of the exercise in this study was heavily intense, whether people were cycling or backhanding a shuttlecock.

Income and other aspects of people’s lifestyles are also likely to matter, he said. The researchers tried to account for socioeconomic factors, but it remains possible, he said, that people who have sufficient money and leisure time to play tennis live longer because they have sufficient money and leisure time, not because they play tennis.

Still, he suspects that the social aspects of racket games and other team sports are a primary reason that they seem to lengthen lives, he said.