Should you track step count or workout duration?

FFor years, federal physical activity guidelines have told Americans how much time they should spend moving each week: at least 150 minutes, or 75 minutes if workouts are particularly vigorous. But the popularity of wearable fitness devices has many people obsessively tracking their step counts, often aiming for the goal of 10,000 per day (although some studies suggest that number is arbitrary).

Is the length of your workout or daily step count a better measure of well-being?

“Both are good metrics,” says Dr. Rikuta Hamaya, a preventive medicine researcher at Brigham and Women’s Hospital in Boston and lead author of the new study. But Hamaya and his colleagues wanted to know if one was better than the other, so they devised a direct comparison.

The result to studypublished in JAMA Internal Medicine, is based on data from more than 14,000 North American women who were followed for about a decade. When the study began, all of the women were at least 62 years old and had no cardiovascular disease or cancer. They were asked to wear an activity monitor for a week, removing it only to sleep, shower or swim. From this data, the researchers calculated how many steps people took per day, as well as how much time they spent performing moderate to vigorous physical activities, such as cycling, running or brisk walking.

see more information: Why walking isn’t enough when it comes to exercise

Among the women in the study, the average number of daily steps was about 5,200, while the average duration of physical activity was about an hour per week. People who exercised more also tended to walk more, but the two measures weren’t perfectly in sync. This is in part because slower forms of walking, like walking around the house, aren’t necessarily intense enough to register as moderate to vigorous activity on a fitness tracker, but they still count toward the number of steps taken.

So which measure was best? Both were equally good: however you measured it, more movement meant better health and longevity.

Over the years of follow-up, about 9% of women in the study died and 4% developed cardiovascular disease. Compared to the more sedentary members of the group, the most active women were significantly less likely – by 30% or even more – to experience either outcome, regardless of how the researchers measured their activity. In the end, Hamaya says, there wasn’t a “material difference” between the two metrics, at least for the people in the study.

But it’s important to note that the study only focused on older, predominantly white American women who were healthy when the research began, so it’s impossible to say whether the same conclusion applies to everyone. Younger adults, for example, may benefit more from vigorous activity, although more research is needed to know for sure.

Still, the research result is encouraging, says Hamaya, because it suggests that — at least for certain groups of people — there is no single, best way to assess aptitude, and that people can look to whatever benchmark seems right to them. “If someone likes counting steps, go ahead,” he says. “Or if someone likes to tell [workout] time, that would be a good choice” too.