This UK Biobank study examined how the duration and fragmentation of physical activity bouts (from accelerometry) relate to future risk of dementia, depression, and anxiety, using a multi-modal design across a large prospective cohort.
Longer, less fragmented physical activity bouts were associated with reduced risk of dementia, depression, and anxiety; shorter, more fragmented activity patterns were linked to higher risk of these outcomes.
Accelerometry data and outcomes may be subject to reverse causation (prodromal disease affecting activity patterns); the UK Biobank cohort skews healthier and more educated than the general population, limiting generalizability; a single accelerometry assessment may not capture habitual long-term activity patterns.
Clinicians should encourage patients to accumulate physical activity in longer, sustained bouts rather than fragmented bursts, as this pattern is linked to lower risk of dementia, depression, and anxiety. Fragmented activity may be a useful clinical marker to flag patients for preventive intervention.
