Scientists Identify One Fitness Habit That May Matter Most For Longevity

Should you go all in on walking—or switch up your workouts during the week? A new study compares the longevity benefits of various types of popular exercises.

While it's well documented that exercise lowers your associated mortality risk , few studies so far have investigated whether or not diversifying your exercise matters. But according to a new Harvard University study, in the long term, exercise variety makes a significant difference in longevity, regardless of how long you sweat.

The study, published on January 20 in BMJ Medicine , focused on 111,000 nurses and health professionals who routinely completed surveys about their exercise habits over a span of 30 years. The participants logged their total time spent on multiple physical activities, including gardening, biking, running, strength training, tennis, climbing stairs, and yoga. The study authors then grouped participants by activity variety.

The most diverse group—those who engaged in the highest number of distinct activities per week—had a 19 percent lower associated mortality risk than the least diverse group, results showed.

The takeaway? “It's probably better to spread the limited energy on multiple physical activities instead of sticking to a single high-intensity one,” says Yang Hu, the study author and a research scientist at Harvard's department of nutrition.

However, since the data is self-reported, participants may have exaggerated their weekly exercise. The study also observed a trend between exercise diversity and longevity, but cannot conclude that variety in movement directly causes lower mortality without a clinical trial. “The findings should be interpreted cautiously,” says Duck-chul Lee, director of the Physical Activity Research Center at the University of Pittsburgh.

Still, the study is well done and interesting, Lee adds. Instead of focusing solely on the advantages of combining aerobic exercise and weight-lifting, like prior sports research suggests, “this study includes various types of popular exercises.”