The effects of a physical and cognitive training intervention vs. physical training alone on older adults' physical activity: A randomized controlled trial with extended follow-up during COVID-19.

BACKGROUND Executive functions underlie self-regulation and are thus important for physical activity and adaptation to new situations. The aim was to investigate, if yearlong physical and cognitive training (PTCT) had greater effects on physical activity among older adults than physical training (PT) alone, and if executive functions predicted physical activity at baseline, after six (6m) and twelve months (12m) of the interventions, one-year post-intervention follow-up and an extended follow-up during COVID-19 lockdown. METHODS Data from a single-blinded, parallel-group randomized controlled trial (PASSWORD-study, ISRCTN52388040) were utilized. Participants were 70-85 years old community-dwelling men and women from Jyväskylä, Finland. PT (n = 159) included supervised resistance, walking and balance training, home-exercises and self-administered moderate activity. PTCT (n = 155) included PT and cognitive training targeting executive functions on a computer program. Physical activity was assessed with a one-item, seven-scale question. Executive functions were assessed with color-word Stroop, Trail Making Test (TMT) B-A and Letter Fluency. Changes in physical activity were modeled with multinomial logistic models and the impact of executive functions on physical activity with latent change score models. RESULTS No significant group-by-time interaction was observed for physical activity (p>0.1). The subjects were likely to select an activity category higher than baseline throughout the study (pooled data: B = 0.720-1.614, p<0.001-0.046). Higher baseline Stroop predicted higher physical activity through all subsequent time-points (pooled data: B = 0.011-0.013, p = 0.015-0.030). Higher baseline TMT B-A predicted higher physical activity at 6m (pooled data: B = 0.007, p = 0.006) and during COVID-19 (B = 0.005, p = 0.030). In the PT group, higher baseline Letter Fluency predicted higher physical activity at 12m (B = -0.028, p = 0.030) and follow-up (B = -0.042, p = 0.002). CONCLUSIONS Cognitive training did not have additive effects over physical training alone on physical activity, but multicomponent training and higher executive function at baseline may support adaptation to and maintenance of a physically active lifestyle among older adults.