The effects of a moderate physical activity intervention on physical fitness and cognition in healthy elderly with low levels of physical activity: a randomized controlled trial

Background: Increasing physical activity is one of the most promising and challenging interventions to delay or prevent cognitive decline and dementia. Methods: We conducted a randomized controlled trial to assess the effects of a physical activity intervention, aimed at increasing step count, in elderly with low levels of physical activity on measures of strength, balance, aerobic capacity, and cognition. Participants were assigned to 9 months of exercise counseling or active control. Results: The intention-to-treat analyses show that the intervention, compared to control, increases the level of physical activity, but has no significant effect on physical fitness and cognition. Those who increased their physical activity with 35% or more show significant improvements in aerobic capacity, gait speed, verbal memory, executive functioning, and global cognition, compared to those who did not achieve a 35% increase. Limitations: The number of participants that achieved the intended improvement was lower than expected. Conclusion: Responder analyses suggest an improvement of physical fitness and cognition in those who achieved an increase in physical activity of at least 35%. Trial registration: The trial protocol is registered at the Dutch Trial Register NL5675, August 1, 2016.