Physical Activity, β-Amyloid Burden, Cognitive Decline, and Neurodegeneration

Growing evidence demonstrates that lifestyle behaviors modify dementia risk. Investigators from the Harvard Aging Brain Study assessed the effects of physical activity on β-amyloid burden, longitudinal cognitive decline, and neurodegeneration in cognitively normal older adults.

Baseline physical activity was the daily number of steps counted over 5 to 7 days by a waistband pedometer (~5500 daily steps in these participants); β-amyloid burden was determined via Pittsburgh Compound B positron emission tomography, and vascular risk was calculated with the Framingham Heart Study cardiovascular disease risk score. Longitudinal neurodegeneration was measured by loss of gray matter and cortical thickness seen on brain MRI, and a cognitive composite…