 AIM 1: Determine the feasibility and acceptability of a 26-week, 3-4 days per week, structured EXER regimen among middle-aged adults with FH of AD. Hypothesis: The investigators will successfully enroll the 30 participants 15 each in EXER and usual physical activity groups targeted for this study. At least 90 of the participants within the EXER group, called the enhanced physical activity group, will complete 80 of scheduled training sessions. 