Physical Activity and Episodic Memory: An Analysis of Longitudinal Associations Over 12 Years

With the increasing prevalence of Alzheimer’s and related dementias, it is becoming a growing public health concern to identify modifiable risk factors to prevent cognitive decline. Previous research suggest that physical exercise may promote cognitive function in aging. However, most of this research is based on experimental or cross-sectional studies and fewer studies have studied longitudinal associations over longer time frames. In the present study, we examined how physical activity is related to cognition in older adults. To do so, we applied multilevel models to data from 29,740 participants (age at baseline: M = 63 years, SD = 11 years, 50 to 102 years) from years 2004-2016, measured biennially (waves 7-13) of the Health and Retirement Study. Our findings showed that at the between-person level, those who practiced light, moderate, and vigorous- physical activity more frequently than others showed higher levels of episodic memory than others at the age of 70. At the within-person level, participants performed better than usual on a test of episodic memory on occasions when they reported more frequent physical activity of light, moderate and vigorous intensity. More frequent vigorous physical activity was related to less age-related decline in episodic memory, while the frequency of moderate physical exercise was unrelated to age-related change in memory. Contrary to our expectations, more frequent light physical exercise was related to more age-related decline in episodic memory. We discuss the implications of these findings for future research and practice.