The health benefits associated with meeting physical activity guidelines may vary with the length of individual activity sessions. Digest
Physical activity guidelines recommend 150–300 minutes of moderate or 75–150 minutes of vigorous activity per week, but it remains unclear whether short bursts spread throughout the day are linked to long-term benefits similar to longer bouts of exercise. A new study examined how these different activity patterns were associated with the risk of death and cardiovascular disease.
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The study included 96,054 middle-aged and older adults from the UK Biobank, with an average age of 62. Researchers used seven days of data from wrist-worn activity trackers to estimate how much moderate-to-vigorous physical activity (MVPA) each person accumulated in short bursts of less than 10 minutes versus longer stretches of about 10 minutes or more. They then examined how the amount of activity accumulated in each activity pattern was associated with the risk of death from any cause and new cardiovascular disease events over about eight years, while accounting for major demographic, health, and lifestyle factors. For each activity pattern, the researchers compared higher amounts of activity with the level separating the least-active 10% of participants from everyone else.
- Compared with a reference level of 65 minutes a week of brief MVPA, 150 minutes a week was associated with a 48% lower rate of death from any cause and a 33% lower rate of new cardiovascular disease events. Adding more brief activity beyond 150 minutes was linked to little additional reduction in either outcome.
- Compared with a reference level of 38 minutes a week of MVPA accumulated in longer bouts, 300 minutes a week was associated with a 49% lower rate of death from any cause and a 35% lower rate of new cardiovascular disease events. Unlike brief activity, the association continued beyond 300 minutes.
- At high levels of brief MVPA, more activity accumulated in longer MVPA bouts was still linked to lower rates of death and cardiovascular disease. But at high levels of longer MVPA, adding brief activity beyond about 150 minutes a week was linked to little further difference in risk.
Studies of short activity breaks have shown improvements in blood pressure and blood glucose, demonstrating that activity does not have to be sustained for long periods to benefit cardiovascular and metabolic health. Longer activity bouts can provide the same benefits while keeping cardiovascular and metabolic demands elevated for longer. This may create a stronger training stimulus and promote additional adaptations, particularly improvements in cardiorespiratory fitness, the ability of the heart, lungs, and circulation to support prolonged activity.
The findings are observational and are based only on a short snapshot of participants' physical activity habits, so they cannot prove that brief or longer activity caused the differences in death and cardiovascular disease risk. Even so, the study suggests that brief bouts of MVPA can provide substantial health benefits, while they may not fully replace exercise sustained for longer periods. In this clip, I discuss how exercise timing, type, and frequency impact heart aging and long-term cardiovascular health.