Experimental Evaluation of the Joint Effects of Exercise and Sedentary Behavior on Cognitive Function

The objective of this study was to evaluate the potential joint effects of sedentary behavior and exercise on cognitive function.

Participants (M_age = 20 yrs) were randomly assigned to one of three experimental groups. The No Exercise Group (n = 19) was instructed to reduce steps to less than 5000/day and were not allowed to exercise for one-week; the Reduced MVPA (moderate-to-vigorous PA) Group (n = 18) was instructed to reduce steps to less than 5000/day but exercised for 50% of their previously reported vigorous PA for one-week; and the Control Group (n = 20) maintained normal activity for one-week. Cognitive functions (via Stroop and Trail Making tasks) were assessed at baseline, post-intervention, and after one week of resumed normal activity for the intervention groups.

Statistically significant main effects for time were observed for Stroop Congruent (F_time = 11.7, p < 0.001, η ² _p = 0.18), Stroop Incongruent (F_time = 19.4, p < 0.001, η ² _p = 0.26), Stroop Control (F_time = 54.4, p > 0.001, η ² _p = 0.50), Trail Making-A (F_time = 19.1, p < 0.001, η ² _p = 0.26) and Trail Making-B (F_time = 13.8, p < 0.001, η ² _p = 0.21) tasks. However, there were no statistically significant group x time interactions (all p's > 0.05) for any of the cognitive parameters.

These experimental findings do not suggest an interaction effect between sedentary behavior and physical activity on cognitive function.