1)Univariate and 2) age and sex adjusted linear regression models were used to evaluate the associations between physical activity measures (exposure) and ADRD biomarkers

2)Interactions were used to examine whether the associations were modified by APOE genotype, sex, and age.

•Mean age was 75.9 ± 6.1 years and 61.2% women

•Only age modified the associations between sleep duration and Aβ40 (β: -0.04, p = 0.006) suggesting that the association was stronger in younger participants.

•Greater total activity time and more time spent in moderate-intensity physical activity were associated with lower levels of p-tau217 (β: =-0.27, p = 0.073), Aβ42 (β: -0.96, p=0.065), Aβ40 (β = -8.35, 0.043), and APS2 (β =-2.08, p =0.082) but not with Aβ42/ Aβ40.

•Greater sedentary time Aβ40 (β = -6.05, 0.025) and longer sleep (β = 2.39, 0.049) showed associations with Aβ40

•Unexpectedly higher sedentary levels were also associated with  higher Aβ42/Aβ40

•In this preliminary analysis, greater total physical activity and moderate-intensity physical activity were associated with more favorable plasma ADRD biomarker profiles, including lower levels of p-tau217, Aβ42, Aβ40, and APS2, although several associations did not reach conventional levels of statistical significance.

•Associations between sedentary behavior and ADRD biomarkers were less consistent.

•As this is an ongoing study with a currently modest sample size, the present findings should be considered preliminary and hypothesis-generating.

•Planned analyses in the full cohort of approximately 112 participants will provide substantially greater statistical power to clarify the direction, magnitude, and robustness of these associations and to determine whether physical activity, sedentary behavior, and sleep are independently associated with blood-based ADRD biomarkers.