A week of wrist data from 86,196 people, and a gap between men and women that may not hold

Activity guidelines give everyone the same target: about 150 minutes a week of moderate-to-vigorous movement. Men and women differ in body size, muscle and fitness, so researchers keep asking whether the same minutes buy the same benefit.

A study published in Frontiers in Public Health on October 28 tried to answer that with motion data instead of memory. Zihao Zheng and colleagues at Shengjing Hospital of China Medical University in Shenyang used the UK Biobank. Between 2013 and 2015, its participants wore a small accelerometer on the wrist, day and night, for seven days.

What the wrist recorded

The analysis covered 86,196 adults, 43.1% of them men, with an average age of about 56. A model trained on labelled recordings sorted each half minute into types of movement. Anything at three times resting effort or more counted as moderate-to-vigorous activity.

Anyone averaging at least 150 minutes a week was classed as active. Men logged about 330 minutes a week on average, and women about 241. About 74% of the men and 60% of the women cleared the line.

The team then followed everyone for a median of 7.93 years. In that time, 5,195 people died.

Fewer deaths in both groups

Being active went with a lower risk of death from any cause, for men and for women. Active men had a 30% lower risk than inactive men, a hazard ratio of 0.70. Active women had a 19% lower risk than inactive women, a hazard ratio of 0.81.

The shape differed too. In men, more minutes kept lining up with lower risk. In women, the authors describe the gradient for death from any cause as modest.

Why we would not lean on the gap

The headline difference between the sexes passed the main test, with an interaction p-value of 0.032. It also held when the first year of follow-up was removed. But when the authors filled in missing data with multiple imputation, it no longer reached significance, at 0.082.

The team also looked at 447 other health outcomes. Thirty-five showed a nominal difference between men and women. None survived correction for testing so many at once. The authors say their ratios for converting men's minutes into women's are exploratory, and should not be read as fixed conversion factors.

There are wider limits. This is an observational study, so it shows links, not causes. UK Biobank volunteers tend to be older, British and better off than the population. Most background details were collected years before the wrist week. And one week of wear may not reflect a whole year.

Where Soma fits

Soma is a general wellness product, not a medical device, and nothing here is advice on how much to move. What stands out to us is the method: one week from a wrist device, used to describe years. A single week is a snapshot. The Soma app, which isn't available yet, is being built to read what your phone and watch already record in Apple Health, so the picture builds over many weeks instead of one. Soma Axon, the pod we are still building, uses the same light, cameras and stance every week, and shows each value with its margin of error, so a change over time is easier to trust. We wrote more about that in The same instrument, every week.

Sources, as of November 3, 2026: Zheng and colleagues, Frontiers in Public Health, published under CC BY 4.0. This post describes research and isn't medical advice.