INTRODUCTION: Physical activity (PA) is associated with brain health in older adults. However, it is unknown whether the current physical activity recommendations (PAR) impart substantive benefit. The objective of this study was to compare temporal lobe volumes between older adults who met PAR and those who did not.

METHODS: Ninety-one enrollees from the Wisconsin Registry for Alzheimer's Prevention wore an accelerometer for seven consecutive days to quantify their PA behaviors and underwent a T-1 anatomic magnetic resonance imaging scan. Participants were categorized as either having met PAR or not based on the US Department of Health and Human Services recommendations of 150 minutes of moderate-to-vigorous physical activity per week.

RESULTS: Participants who met PAR possessed significantly greater inferior (η(2) P = .050) and anterior (η(2) P = .055) temporal lobe volumes compared with those who did not (P < .05).

DISCUSSION: Individuals at-risk for AD experience accelerated rates of brain atrophy. These results suggest that regular engagement in PA at or above PAR could attenuate this decline.