Dr Conor Cunningham, IPH Public Health Interventions Officer said, in a February 2020 review in the Scandinavian Journal of Medicine & Science in Sports, 

"This research highlights the benefits of physical activity to our physical and mental health in older age. For some time, we have known of the benefits of physical activity for our physical health; however, what is important about this research is that it highlights compelling emerging evidence of the positive effects of being physically active on our mental health--including depression, cognition, and dementia and Alzheimer's disease,"