You’ve probably heard this one a few times before: Research suggests that exercise is linked to a longer life.

What’s more surprising is that a tiny amount of activity could have a noticeable effect, according to a study published Tuesday in the British Journal of Sports Medicine that included more than 13,000 women with an average age of 72. For these women, walking just 4,000 steps one day a week was enough to start seeing a decline in likelihood of dying or developing heart disease over the course of the study. The findings suggest that walking a mile or two once a week is still beneficial, even if your other days are less active. 

Small steps, big change

Fitness apps and wearable trackers often set a goal for users to reach 10,000 steps per day. Yet many experts agree that number is arbitrary. Amanda Paluch, a professor of kinesiology at the University of Massachusetts in Amherst who studies step counts as a measure of physical exercise, says the popular benchmark seems to have been inspired by a Japanese pedometer device made decades ago. “It has not been backed up by scientific evidence,” she says.

Still, steps are a handy way to think about physical activity, so researchers have been working to understand exactly how many per day are linked to improved health.

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In the new study, participants wore step counters for a week, and the researchers recorded the number of days each woman achieved step counts greater than 4,000, 5,000, 6,000, and 7,000. Then, for more than a decade, they tracked whether the women developed cardiovascular disease or died.

The goal was to determine whether even relatively small numbers of steps, logged on just a handful of days, would affect the women’s health, says study author Dr. Rikuta Hamaya, an instructor in medicine at Brigham and Women’s Hospital.

Women who walked 4,000 steps once or twice a week experienced a 27% lower risk of developing cardiovascular disease and a 26% lower risk of dying during the study period, compared to those who didn’t—a substantial difference.

Shifting from an all-or-nothing mindset

The new study suggests “it’s not all or nothing…even just starting with one day can be incredibly meaningful for your health,” said Paluch, who was not involved in the work. The findings are similar to her own previous research suggesting that even 6,000 steps a day are linked to lower risk of heart disease in adults aged about 60. The new research is also reminiscent of other teams’ work on “Weekend Warriors,” or people who pack their exercise into just a day or two a week but see better health outcomes than those who don’t exercise.

Dr. Shaan Khurshid, a cardiac electrophysiologist at Massachusetts General Hospital, agrees that even a modest amount of exercise can have meaningful health benefits. “[That finding] enables us to empower patients by saying…even if you’re not exercising every day or walking every day, you’re still getting a benefit from that,” he says.

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Other factors might influence the link between movement and health. The researchers can’t conclude, based on observing study participants, that movement definitively caused their better health outcomes. Preexisting frailty could have been at play, as well—although the researchers did their best to control for this, there’s always the chance that some of the people who walked very little did so because they were already not in the best of health.

Plus, Hamaya points out, this study followed only older, mostly white women. More diverse studies with younger people are needed to determine the effects of step counts for other groups.