New research involving more than 4.2 million people across 30 countries suggests that when and why people exercise may matter for brain health, with leisure time physical activity linked to a lower risk of dementia, while strenuous physical work is associated with a higher risk.
The findings do not mean that physical activity at work causes dementia. Instead, researchers say the results highlight an important difference between exercise that people choose to do.
People who reported higher levels of recreational physical activity had a 24% lower risk of dementia compared with those who were least active during their free time. The apparent benefit increased as activity levels rose before eventually reaching a point where additional exercise is not linked to substantially greater protection.
Researchers say voluntary activities such as walking, cycling or swimming may offer several benefits because people can usually control their pace, duration and rest periods.
Regular exercise can also support cardiovascular health, improve blood flow and help manage blood pressure, blood sugar and weight, all factors that may influence brain health.
Jobs involving heavy lifting, repetitive movements, long hours or limited breaks can place different demands on the body than recreational exercise. Workers may also face additional challenges, including workplace stress, noise, pollution and limited control over their schedules.
These differences may help explain what scientists call the “physical activity paradox,” in which exercise during leisure time is often associated with better health outcomes, while intense physical activity at work does not always provide the same benefits.
Research suggests that access to enjoyable exercise, adequate rest and healthier working conditions may be important for long-term health.
