Alzheimer's Prevention Through Exercise (APEx)

Inclusion Criteria:

• Clinical Dementia Rating 0 (nondemented)
• Age 65 or older
• Florbetapir PET evidence of cerebral amyloidosis
• Sedentary or underactive by the Telephone Assessment of Physical Activity
• Stable doses of medications for 30 days.
• Clinician judgment regarding subject's health status and likelihood to successfully complete the 1-year exercise intervention

Exclusion Criteria:

• Clinically significant major psychiatric disorder (e.g., Major Depressive Disorder) according to standard criteria or significant psychiatric symptoms that could impair the completion of the study
• Clinically-significant systemic illness that may affect safety or completion of the study
• History of clinically-evident stroke
• Clinically-significant infection within the last 30 days
• Active cardiac condition (e.g. angina, myocardial infarction, atrial fibrillation) or pulmonary condition in the past 2 years that, in the investigator's opinion, could pose a safety risk to the participant-unless cleared for exercise by the participant's primary care physician or cardiologist.
• Uncontrolled hypertension within the last 6 months
• History of cancer in the last 5 years (except non-metastatic basal or squamous cell carcinoma)
• History of drug or alcohol abuse as defined by DSM-IV criteria within the last 2 years
• Insulin-dependent diabetes mellitus
• Significant pain or musculoskeletal disorder prohibiting participation in an exercise program
• Unwillingness to undergo or contraindication to brain MRI scan.
• History within the last 5 years of primary or recurrent malignant disease with the exception of resected localized cutaneous squamous cell carcinoma, basal cell carcinoma, cervical carcinoma, or prostate cancer.