Physical Activity and Dementia Risk, a Surprising Paradox
A huge and well conducted review of 74 research projects studying the effects of physical activity on the probability of developing dementia has produced a surprising result. (1) Although the guidelines produced by the WHO and the Lancet Commission recommend physical activity, this systematic review (the name given to this type of research method) combined the data from all 74 studies using a statistical technique called meta-analysis, and found that leisure-time physical activity (walking, running, cycling, swimming, sports, recreational exercise) was associated with a 24% lower risk of all-cause dementia. This supports the view that exercise undertaken during leisure time contributes to better brain health and lower dementia risk. Occupational physical activity, however, was associated with a 20% higher risk of dementia.
An editorial by Kivimäki & Hamer (2) examines this apparent paradox, explaining it by noting that people in physically demanding jobs were, on average, less well educated, experienced the effects of deprivation earlier in life, and were more exposed to air pollution: in short, three social factors that increase the risk of dementia in their own right.
So physical activity in retirement reduces your risk of dementia, and people who had physically demanding jobs should not simply spend their retirement sitting still, but should use the time freed from the tyranny of work to take up new, enjoyable activities.
REFERENCES
Feter N, Iso-Markku P, Markarian T, Luong DM, Gunnink J, Schröder N, et al. (2026) Domain-specific physical activity levels and risk of dementia: a systematic review and meta-analysis. The Lancet Public Health. 2026;11(9):e650 to e664.
Kivimäki M, Hamer M. (2026) Physical activity across work and leisure for dementia prevention. The Lancet Public Health. 2026;11(9):e586 to e587.