Just a few more minutes of daily activity could make a meaningful difference for longevity. Digest
Public health estimates often treat physical activity as a threshold, meeting guidelines or not, even though most people change behavior in smaller steps. A large new analysis asked a practical question: if adults moved just a little more, or sat a little less, how much might population mortality shift?
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The researchers pooled individual data from 135,046 adults aged 40 years and older across cohorts in Norway, Sweden, and the United States, plus a separate analysis in the UK Biobank. Participants wore accelerometers (wearable devices that record movement) for a single measurement period at the start and were followed for mortality for about eight years on average. The team modeled "potential impact fractions," meaning the estimated proportion of deaths that could be avoided under specified behavior shifts, using two strategies: targeting the least active or most sedentary fifth of participants, or shifting behavior in everyone except the most active fifth.
- When a 5-minute-per-day increase in moderate-to-vigorous physical activity (MVPA) was modeled only in the least active 20% of participants, the analysis estimated that 6% of all deaths in the entire study population could have been prevented during the follow-up time.
- When the 5-minute MVPA increase was extended to the least active 80% of participants, the estimated share of deaths prevented rose to 10%.
- A 10-minute-per-day increase in MVPA was estimated to prevent about 9% of all deaths when applied to the least active 20%, and about 15% of all deaths when extended to the least active 80%.
- At the individual level, this translates to a steep risk reduction at very low activity levels: increasing MVPA from about 1 to 6 minutes per day was associated with roughly a 30% lower mortality risk, and increasing from 1 to 11 minutes per day with about a 42% lower risk.
- Reducing sedentary time by 30 minutes per day was associated with 3% of deaths prevented when targeting the most sedentary group and 7% when applied more broadly across the population.
- This effect was driven by participants who sat for more than about eight hours per day, as reductions below this level showed little association with mortality.
MVPA, defined here as activity comparable to walking at about 4–5 km per hour, may influence mortality risk through well-established pathways related to cardiovascular function, glucose regulation, and overall metabolic demand, especially when added to near-zero baseline activity. Because higher MVPA necessarily replaces time spent sitting or in very light activity, its association likely reflects the combined effects of moving more and sitting less. By contrast, reductions in sedentary time were associated with lower mortality only at high baseline sitting levels, suggesting that prolonged inactivity may pose distinct risks that emerge once daily sitting exceeds a high threshold.
Because the study was observational and tracked activity only briefly instead of using a long-term controlled intervention, it cannot establish causation, and unmeasured factors may still influence the results. Even so, the same patterns appeared across different groups and analytical checks, strengthening confidence that small, realistic increases in activity can have meaningful benefits. Episode #98 of the FoundMyFitness podcast distills insights from over 100 podcast interviews with world-class exercise scientists.