Can physical exercise help prevent Alzheimer’s disease? Original paper

In this meta-analysis of prospective cohort studies, middle-aged and older adults who engaged in physical exercise, particularly high-intensity activity, were less likely to develop Alzheimer's disease.

The association between physical exercise and Alzheimer’s disease risk.

A total of 2,068,519 middle-aged and older adults (average ages of 37–83) without apparent signs of mild cognitive impairment or subjective cognitive decline.

The percentages of men and women in the studies were not reported.

A systematic review and meta-analysis of 29 prospective cohort studies was conducted. The follow-up period ranged from 4 to 44 years, with an average of 15 years.

To account for potential confounders, the researchers adjusted the outcomes for age, sex, cognition, education, disease status, cardiovascular risk factors, and ApoE ε4 status (a genetic risk factor for Alzheimer’s disease).

Overall, engaging in physical exercise was associated with a reduction in the risk of Alzheimer’s disease, by 15%. Notably, the reduction varied based on the intensity and duration of the exercise. High-intensity exercise seemed particularly effective and was associated with a 44% reduction in Alzheimer's disease risk, whereas moderate intensity was associated with a 15% reduction.

Low-intensity exercise was not associated with a significant change in Alzheimer’s disease risk. Shorter study durations were associated with more significant risk reductions, and no notable association was observed in studies lasting over 15 years.

Although subgroup analyses were performed, the results still exhibited considerable heterogeneity, suggesting an influence of unaccounted confounders. The researchers also observed that the quality of the included studies was generally moderate but noted considerable variation in study designs and methodologies. This variability might limit the generalizability of these findings.