The relationship between objective physical activity and change in cognitive function.

Abstract

The current study investigated the association between objectively measured physical activity and cognition in older adults over approximately 8 years. We utilized data from 199 cognitively unimpaired individuals from the Australian Imaging, Biomarkers and Lifestyle (AIBL) study, aged ≥60. Actigraphy was used to measure physical activity (intensity, total activity, and energy expenditure) at baseline. Cognition was assessed using a comprehensive cognitive battery every 18-months. Higher baseline energy expenditure predicted better episodic recall memory and global cognition over the follow-up period (p=0.031; p=0.047, respectively). Those with higher physical activity intensity and greater total activity also had better global cognition over time (both p=0.005). Finally, higher total physical activity predicted improved episodic recall memory over time (p=0.022). These results suggest that physical activity can preserve cognition and that activity intensity may play an important role in this association. Greater total physical activity predicts preserved episodic memory and global cognition. Moderate intensity physical activity (>3.7 metabolic equivalents of task [MET]) predicts preserved global cognition. Expending>373 kilocalories per day may benefit episodic memory and global cognition.