Association Between Physical Activity and Cognitive Function: Observational and Genetic Analysis

To combine observational study with Mendelian randomization (MR) to clarify the potential causal relationship between physical activity (PA) and cognitive function (CF).

We performed MR analysis by collecting five PA phenotypes and CF datasets from the IEU Open GWAS project, applying inverse variance weighting to assess causal effects, and conducting sensitivity analyses to ensure the robustness of results. We also extracted data on PA and CF from the CHARLS in 2011 and 2018, including a total of 2,795 participants, and conducted statistical analyses using a generalized linear model.

According to the MR analysis, results showed that aerobic exercises (e.g., swimming, cycling, group exercise classes, bowling) had a significant and stable genetic causal relationship with CF (β = 0.86, p < .001), whereas other PA, such as walking for pleasure (β = 0.40, p = .148), heavy do-it-yourself (DIY) (e.g., weeding, mowing the lawn, carpentry, digging) (β = 0.20, p = .456), strenuous sports (β = 1.06, p =.085), and light DIY (e.g., pruning, watering the lawn) (β = 0.56, p = .01) had no significant or stable correlation with CF. In the observational study, after controlling for confounders and subgroup analysis by sex, we found that maintained moderate-high intensity PA (β = 1.008, p = .049) or increased PA (β = 1.118, p = .042) had a significant protective effect on CF compared to maintained low PA in only the female subgroup.

Maintaining moderate-high intensity PA or increasing from low to moderate-high intensity may have a protective effect on CF among females; aerobic exercises, such as swimming, cycling, group exercise classes, and bowling, may be the most effective activities for protecting CF.