The scientists analysed device-measured physical activity data from more than 135,000 adults in Norway, Sweden, the USA and the UK, with an average age of 64 years and roughly eight years of follow-up. Using hip-worn accelerometers, the researchers could quantify, minute by minute, how much time participants spent in moderate-to-vigorous physical activity (MVPA), light-intensity activity and sedentary behaviour, and link this to mortality records.

Small realistic changes

Rather than asking how many deaths could be avoided if everyone met the WHO guideline of at least 150 minutes of MVPA per week, the group focused on “small, realistic” changes in daily behavior. They estimated potential impact fractions – the proportion of deaths that could be prevented – if people added 5–10 minutes of MVPA or cut 30–60 minutes of sitting from their current baseline levels.

Up to 10% of deaths potentially preventable

In seven cohorts from Norway, Sweden and the USA (about 40,000 participants and 4,895 deaths), a 5‑minute per day increase in MVPA among the least active 20% of adults was associated with preventing around 6% of all deaths. When the same 5‑minute increase was modelled across the population – excluding only the most active 20% – the proportion of potentially averted deaths rose to about 10%.

Reducing sedentary time also mattered, though effects were smaller. A 30‑minute per day reduction in sitting time could prevent an estimated 3% of deaths among the most sedentary and around 7% of deaths if adopted by the majority of adults. Data from the UK Biobank showed somewhat lower, but still meaningful, risk reductions.

Implications for Nordic health systems

The authors argue that for many older and inactive adults, achieving full guideline levels of activity is unrealistic, whereas adding a few minutes of brisk walking or light exercise – and breaking up long sitting spells – is achievable. For Nordic health systems facing an ageing population and high sedentary time, the findings suggest that low-threshold interventions could translate into thousands of prevented deaths if adopted at scale.

Read the article in The Lancet here

This text was partly produced with the help of AI and fact-checked by NLS.