A long-term study has found that remaining physically active throughout adulthood may delay the onset of dementia, and even small amounts of exercise can be helpful.
Dementia is not a specific disease but is rather a general term for the impaired ability to remember, think, or make decisions, which interferes with doing everyday activities, the US Centres for Disease Control says.
It affects about 44 million people globally and that number is projected to triple by 2050.
About 40 per cent of the risk of dementia may be attributed to factors that can be modified. Physical activity is one such factor and has been linked to a modest reduction in the risk of all-cause dementia, cognitive decline, and later-life cognition.
The study conducted by researchers at University College London and published online in the Journal of Neurology Neurosurgery and Psychiatry, examined data from 1,417 individuals who completed surveys regarding their exercise habits at various stages of adulthood, spanning from ages 36 to 69.
Participants who remained physically active at least once to four times a month during all five survey periods performed better on cognitive tests at age 69 compared to those who exercised frequently during only one period.
The study — which set out to assess how timing, frequency and maintenance of being physically active, spanning over 30 years in adulthood, is associated with later-life cognitive function — also found that individuals who began exercising in their 60s showed improved cognitive function compared to those who were inactive.
Engaging in leisure-time physical activity, even at light levels, at any point in adult life has a positive effect on cognition, and the benefits accumulate over time, the study concluded.
While factors such as education, childhood attainment, and socio-economic background can affect the link between exercise and brain health, the positive association between exercise and cognitive performance remained significant even when these factors were taken into account.
Even though factoring in childhood cognitive ability, household income, and education weakened the observed associations, the findings remained statistically significant.
The study used a large, representative sample of individuals born across mainland Britain from the longest continuously running birth cohort to assess the relationship between physical activity and cognitive state and memory in later life.
Limitations to the study include a disproportional attrition of socially disadvantaged and less healthy participants and the exclusive representation of white participants. The study only uses self-reported leisure-time activity and does not consider exercise adherence, intensity, or duration.