Differential associations between subjective and objective physical activity and memory across adulthood: a specification curve analysis

Previous studies yield mixed findings on the relationship between moderate-to-vigorous physical activity (MVPA) and episodic memory, potentially due to differences in measurement type (subjective or objective) or variable selection (total MVPA or number of MVPA bouts). To examine this issue, we assessed the association between MVPA and memory with subjective self-report measures (International Physical Activity Questionnaire, Multifactorial Memory Questionnaire, Cognitive Change Index) and objective measures (actigraphy, standardized memory tests) in 172 participants (18–86 years, mean age = 55.4 years). Exploratory specification curve analysis was used to assess the relationship between MVPA and memory across operationalizations while mitigating potential researcher bias in the selection of model specifications. Objectively measured percentage of day in MVPA was positively associated with objective memory performance, whereas subjective MVPA was not associated with subjective or objective memory. Time spent in MVPA bouts was positively related to self-reported memory abilities, and number of MVPA bouts was negatively associated with objective verbal episodic memory performance. Findings did not vary by age. The differential relationships across measurement types suggest that subjective and objective measures and their various operationalizations capture distinct aspects of MVPA and memory, emphasizing the importance of measurement choices and caution when comparing results using differing methodologies.