Association Between Accelerometer-Assessed Physical Activity and Cognitive Function in Older Adults: A Cross-Sectional Study

Abstract

Objective Research suggests that physical activity (PA) improves cognitive function across various domains. However, the specific role of different PA measures, including step count, remains to be explored. Our aim was to assess the correlation between objectively measured PA and cognitive function. Methods We included 663 adults, aged ≥66 years, from the Swedish SNAC-K study (2016–2019). Global cognition and three cognitive domains (processing speed, executive function, and episodic memory) were assessed with validated tests. PA was measured through ActivPAL3 accelerometers. We applied age-stratified (<70 vs. ≥80 years), multi-adjusted, quantile regression to examine the cross-sectional associations between cognitive function and PA, considering steps/day and time spent in moderate-to-vigorous PA (MVPA). Results Each 1000-step increment (β = 0.04; 95% CI: 0.01, 0.07) and each additional hour of MVPA per day (β = 0.28; 95% CI: 0.02, 0.54) were correlated with better processing speed in the youngest-old, but not in the oldest-old. When further stratifying by MVPA (<60 min vs. ≥60 min/week), each 1000-step increment was associated with better processing speed in the youngest-old, regardless of their MVPA levels. Conclusion Our study links accelerometer-assessed PA (steps and MVPA) with better processing speed in the youngest-old adults. Step count correlated with processing speed regardless of intensity. Further research is needed to determine the directionality of these associations.