Vigorous activity tied to lower death risk at 12 minutes a week, the same as 150 moderate minutes

Exercise guidelines contain a quiet piece of arithmetic. Adults are told to get 150 minutes a week of moderate activity or 75 minutes of vigorous activity, which treats one strenuous minute as worth two easier ones. Anyone who has traded a brisk walk for a shorter run has used that exchange rate, usually without knowing where it came from.

A study of 147,414 adults suggests the rate is far too low. Michael Stein, Michael Leitzmann and colleagues at the University of Regensburg pooled motion-sensor recordings from two national cohorts in Germany and the United Kingdom and followed the wearers for about eight years. Writing in the International Journal of Behavioral Nutrition and Physical Activity, they report that about 12 min of vigorous activity per week yielded mortality reductions comparable to 150 min of moderate activity. That is one vigorous minute for roughly every twelve moderate ones. Light activity counted too, but it took about 510 minutes a week to match.

Where the two-for-one rule for vigorous activity comes from

World Health Organization guidance, last updated in 2020, recommends 150 to 300 minutes of moderate-intensity activity a week, 75 to 150 minutes of vigorous-intensity activity, or some equivalent combination of moderate-intensity and vigorous-intensity exercise. Moderate means effort like a brisk walk. Vigorous means effort that leaves a person breathing hard, such as running or cycling uphill.

The halving has a laboratory origin. Exercise physiologists rank activities by how much energy they burn, and in the questionnaire studies that guidelines were built on, vigorous activity is assumed to require twice the per-minute energy expenditure of moderate activity. Energy burned became a stand-in for health gained.

Questionnaires are a blunt way to test that assumption. Most of us remember a gym session and forget the run for a bus, and we are poor judges of how hard we were working. Wearable sensors record movement second by second, and as cohorts wearing them have matured, researchers have been able to ask what each minute at each intensity is associated with.

How the study measured activity intensity in 147,414 adults

The Regensburg team combined the German National Cohort, known as NAKO, with UK Biobank. In Germany, among 205,415 participants, 72,553 wore a hip-mounted accelerometer, a small sensor that records acceleration in three directions. In Britain 103,578 wore one on the wrist. Each person kept the device on for seven consecutive days, and after removing poor recordings the researchers had 147,414 adults aged 40 to 74.

Every minute of movement was sorted into light, moderate or vigorous by how forceful the acceleration was. Deaths were then counted from national records. The mean follow-up was 7.9 years, during which 5,545 deaths occurred, fewer than four for every hundred participants.

Those who move more differ from those who move less, so the comparisons were adjusted for age, sex, education, employment, alcohol consumption, smoking status, prevalent chronic disease, body weight, grip strength, sitting time and sleep. Using two cohorts with different devices worn in different places was deliberate. If the same pattern appeared on the hip in Germany and on the wrist in Britain, it would be harder to dismiss as a quirk of one gadget.

How light, moderate and vigorous activity compared for mortality

All three intensities went with fewer deaths. Compared with recording no activity at that level, 150 minutes a week of moderate activity was associated with a death rate about 30% lower. The curves were steepest at the bottom: the authors write that mortality declined sharply as individuals moved out of the lowest activity range, regardless of intensity, indicating that any activity is preferable to almost none.

What differed was the price of the same benefit. The 30% figure took 150 moderate minutes, about 510 light minutes, or about 12 vigorous ones. Light activity is the slow walking and pottering that fills much of an ordinary day, and eight and a half hours of it a week is not hard to reach. Twelve minutes of vigorous effort is less than two minutes a day.

The team then asked a more practical question. Suppose total active time stays the same and only the mix changes. Reallocating 15, 30, 45, or 60 min per week from light to moderate activity corresponded to approximately 3%, 6%, 9%, and 11% lower mortality. Shifting time from either light or moderate activity to vigorous activity yielded larger reductions, ranging from about 18% to 30%.

Vigorous activity also behaved differently in kind. Moderate activity showed a steady gradient, with more minutes going with fewer deaths. Vigorous activity looked more like a step, with most of the difference lying between doing none and doing any. Those recording 2 to 20 vigorous minutes a week had a death rate about a third lower than those recording none.

The authors warn against the obvious misreading of that number. They write that “these findings should not be interpreted as indicating a minimum effective dose of vigorous-intensity physical activity”, because the result belongs to the whole 2-to-20-minute band and those near the top of it probably account for most of it.

Why vigorous minutes might count for more, and why the gap may be overstated

There are physiological reasons to expect harder effort to do more. In the paper’s words, vigorous activity induces larger, more rapid increases in heart rate and breathing than gentler movement, and it brings stronger gains in fitness, in the working of blood vessel linings and in the body’s response to insulin. Each of those predicts length of life.

There are also reasons to think the twelve-to-one figure flatters vigorous exercise. The study is observational, so it cannot show that the hard minutes caused the longer lives. Anyone who sprints for buses and climbs hills on a bike is, almost by definition, someone whose heart, lungs and joints still allow it. The authors name the problem as reverse causation, the possibility that the outcome is shaping the exposure, and write that preclinical disease or declining functional capacity may reduce participation in vigorous activity prior to death. They dropped the first years of follow-up to limit it, and the results held, but they say unmeasured confounding cannot be excluded.

Measurement adds its own uncertainty. A week of recording has to stand in for years of habit. The boundaries between light, moderate and vigorous are set by acceleration thresholds on which, the authors note, there is limited consensus, and a wrist sensor can score busy arm movements as hard exercise. Accelerometers also miss context: the paper lists the inability of accelerometers to capture contextual information about physical activity, which means lifting weights barely registers.

Then there is who took part. Only 15.6% of those invited joined the German cohort and 5.5% joined UK Biobank, and volunteers for health studies tend to be healthier than their neighbors.

Earlier wearable studies of vigorous activity found the same pattern

The Regensburg analysis is the largest of its kind, and its direction is not new. In 2019 Ulf Ekelund of the Norwegian School of Sport Sciences led a pooled analysis of eight sensor-based cohorts in The BMJ. It found that any physical activity, regardless of intensity, was associated with lower risk of mortality, with the largest step between the least active quarter and the next.

A group at the University of Sydney has since concentrated on the vigorous end, using UK Biobank’s wrist data. Matthew Ahmadi and colleagues reported in the European Heart Journal that among 71,893 adults the five-year risk of death was 4.17% in those who did no vigorous activity and 2.12% in those who did some but under ten minutes a week. They concluded that lower risks may be attainable through modest amounts accrued in short bouts across the week.

The same group looked at adults who said they never exercised at all. In Nature Medicine, Emmanuel Stamatakis and colleagues tracked all-cause, cardiovascular and cancer mortality in 25,241 nonexercisers, counting the brief bursts of vigorous movement that is embedded into everyday life, such as climbing stairs fast. A median of 4.4 minutes a day of such bursts went with a rate of death from any cause that was 26% to 30% lower.

In 2025 the Sydney team put a number on the exchange rate directly. In 73,485 UK Biobank participants, each vigorous minute was worth about four moderate minutes, or 53 light ones, for the same reduction in deaths. The Regensburg figure is steeper still, and its German hip-worn data showed stronger links than the British wrist-worn data, which hints that the wrist may understate the difference.

These studies overlap heavily. Three of the four draw on the same UK Biobank volunteers, so they are closer to one finding examined several ways than to independent confirmations. The German cohort is the part of the evidence that is new.

Do the results change the 150-minute activity guideline?

Not yet, and the authors do not claim they should. They write that “these estimates reflect statistical associations derived from device-measured activity patterns and should not be interpreted as physiological equivalence between activity intensities or as a direct substitution for current physical activity recommendations”.

The WHO guideline rests on systematic reviews of the wider research as well as on energy arithmetic, and its central messages survive this study intact. It holds that some physical activity is better than none and that more is better, both of which the sensor data support. What the new work challenges is the two-for-one conversion between moderate and vigorous minutes. No trial has randomly assigned volunteers to short bursts of vigorous effort and counted deaths, so the conversion the sensors suggest remains an association.

In these data every kind of movement went with longer life, and the hardest minutes went furthest, by a margin the study design cannot fully vouch for.