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What's best? US study compares step-counting to timed workouts

A large US study has looked at whether physical exercise or the goal of reaching a daily step count has a better impact on health, reports TIME.

For years, Americans guidelines have recommended how much time people should spend moving each week – at least 150 minutes, or 75 minutes if workouts are particularly vigorous – but step counting has become the new norm, thanks to the popularity of wearable fitness devices.

And while the the target of 10 000 daily steps (suggested by some studies as an arbitrary number) appears to be a particularly common goal, there has been debate on whether the length of a workout or a daily step count is a better measure of wellness,

“Both are good metrics,” concluded Dr Rikuta Hamaya, a preventive-medicine researcher at Brigham and Women’s Hospital in Boston, who with colleagues, carried out a head-to-head comparison to see which one was better than the other.

The resulting study, published in JAMA Internal Medicine, is based on data from more than 14 000 US women who were tracked for about a decade. When the study began, the women were all at least 62 years old and free of cardiovascular disease and cancer. They were asked to wear an activity monitor for a week, removing it only to sleep, shower, or swim.

From those data, the researchers calculated how many steps people took per day, as well as how much time they spent doing moderate-to-vigorous physical activity like cycling, jogging, or walking quickly.

Among women in the study, the median number of daily steps was around 5 200, while the median physical-activity duration was about an hour per week.

People who exercised more also tended to walk more, but the two measures weren’t perfectly synced. That’s in part because slower forms of walking, like puttering around the house, aren’t necessarily intense enough to register as moderate-to-vigorous activity on a fitness monitor, but still count toward the number of steps taken.

So which measure was better?

Both were equally good: however they measured it, more movement equalled better health and longevity.

Over the years of follow-up, about 9% of women in the study died and 4% developed cardiovascular disease. Compared with the most sedentary members of the group, the more active women were significantly less likely – by 30% or even more – to experience either outcome, no matter how the researchers measured their activity.

In the end, Hamaya said, 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 focused solely on older, predominantly white US women who were healthy when the research began, so it’s impossible to say if the same finding applies to all people.

Younger adults, for example, may benefit more from vigorous activity, although more research is required to say for sure.

Still, the takeaway from the research is encouraging, lead author Hamaya said, because it suggests that, at least for certain groups of people, there is no single best way to assess fitness, and that people can shoot for whichever benchmark feels right to them.

“If someone likes to count steps, go with it,” he says. “Or if someone likes to count workout time, that would be a good choice too.”

Study details

Time- vs Step-Based Physical Activity Metrics for Health

Rikuta Hamaya, Eric Shiroma Jr, Christopher Moore et al.

Published in JAMA Internal Medicine on 20 May 2024

Abstract

Importance
Current US physical activity (PA) guidelines prescribe moderate to vigorous PA (MVPA) time of at least 150 minutes per week for health. An analogous step-based recommendation has not been issued due to insufficient evidence.

Objective
To examine the associations of MVPA time and step counts with all-cause mortality and cardiovascular disease (CVD).

Design, Setting, and Participants
This cohort study analysed data from an ongoing follow-up study of surviving participants of the Women’s Health Study, a randomised clinical trial conducted from 1992 to 2004 in the US to evaluate use of low-dose aspirin and vitamin E for preventing cancer and CVD. Participants were 62 years or older who were free from CVD and cancer, completed annual questionnaires, and agreed to measure their PA with an accelerometer as part of a 2011-2015 ancillary study. Participants were followed up until 31 December 2022.

Exposures
Time spent in MVPA and step counts, measured with an accelerometer for seven consecutive days.

Main Outcomes and Measures
The associations of MVPA time and step counts with all-cause mortality and CVD (composite of myocardial infarction, stroke, and CVD mortality) adjusted for confounders. Cox proportional hazards regression models, restricted mean survival time differences, and area under the receiver operating characteristic curve (AUC) were used to evaluate the associations.

Results
A total of 14 399 women (mean [SD] age, 71.8 [5.6] years) were included. The median (IQR) MVPA time and step counts were 62 (20-149) minutes per week and 5183 (3691-7001) steps per day, respectively. During a median (IQR) follow-up of 9.0 (8.0-9.9) years, the hazard ratios (HR) per SD for all-cause mortality were 0.82 (95% CI, 0.75-0.90) for MVPA time and 0.74 (95% CI, 0.69-0.80) for step counts. Greater MVPA time and step counts (top 3 quartiles vs bottom quartile) were associated with a longer period free from death: 2.22 (95% CI, 1.58-2.85) months and 2.36 (95% CI, 1.73-2.99) months at nine years’ follow-up, respectively. The AUCs for all-cause mortality from MVPA time and step counts were similar: 0.55 (95% CI, 0.52-0.57) for both metrics. Similar associations of these tw metrics with CVD were observed.

Conclusion and Relevance
Results of this study suggest that among females 62 or older, MVPA time and step counts were qualitatively similar in their associations with all-cause mortality and CVD. Step count–based goals should be considered for future guidelines along with time-based goals, allowing for the accommodation of personal preferences.

 

JAMA Internal Medicine article – Time- vs Step-Based Physical Activity Metrics for Health (Open access)

 

TIME Magazine article – Which Is Better: Counting Your Steps or Timing Your Workout? (Open access)

 

See more from MedicalBrief archives:

 

Under 5 000 daily steps still beneficial, say experts

 

Optimal number of daily steps to reduce all-cause mortality varies by age – Meta-analysis

 

Women need half as much exercise as men for longevity – US study

 

Higher daily step counts strongly associated with lower mortality risk

 

Why all physical activity is not equally beneficial

 

 

 

 

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