Brief bursts of vigorous everyday activity were associated with a lower risk of dementia in a study of more than 22,000 adults. Researchers found that accumulating about 3.7 minutes daily was linked to a 48 per cent reduction in risk compared with sedentary participants.
The team analysed UK Biobank data from 22,618 adults, mostly in their early sixties. Participants wore wrist accelerometers for seven days between 2013 and 2015 and were followed for approximately eight years. None had a dementia diagnosis when activity monitoring began. During follow-up, 170 developed dementia.
Dementia occurred in 2.5 per cent of participants doing no exercise, compared with 0.71 per cent among those who performed vigorous daily activities without planned exercise. The proportion was 0.59 per cent among those combining deliberate exercise with everyday exertion.
Activities included climbing stairs, carrying heavy shopping and rushing for a bus. Greater vigorous activity was also associated with larger grey matter volumes in several brain regions and less abnormal white matter tissue.
The findings do not establish that these activities prevent dementia. Because the study was observational, other factors could help explain the association. Undiagnosed dementia might already have reduced some participants’ ability to exercise. Activity measurements also covered only one week, potentially missing changes over subsequent years.
Researchers suggest that improved cardiovascular health could help explain the findings. Possible mechanisms include lower blood pressure and reduced arterial stiffness, which could limit vascular damage in the brain. Movements requiring rapid changes in posture may also engage brain networks involved in coordination and movement.
The results add to research examining incidental activity as a complement to structured exercise. Study author Nicholas Koemel advised gradual increases in activity rather than abrupt changes, noting that sudden increases in exertion could raise the risk of injuries or accidents. Further research could clarify causality.