“Doing moderate exercise several times a week is the best way to keep the mind sharp if you’re over 50,” BBC News reports.

A review of existing data found both aerobic exercise and strength training appeared to improve cognitive functions, such as memory, attention, and how well people carry out tasks.

The review brought together information from 39 studies in the biggest summary of the effects of exercise on mental ability to date.

Previous summaries of research have had unclear results. But this study found most types of moderate to vigorous exercise had a positive effect as long as sessions lasted at least 45 minutes.

The researchers say doctors should recommend people take part in exercise on as many days a week as possible.

Importantly, the study found people benefited even if they were already showing signs of mental decline. This means exercise might help those with early signs of dementia stay mentally alert for longer.

The study provides yet another reason to keep active in later life – both the mind and the body should benefit.

It’s recommended that adults do at least 150 minutes of exercise a week, ideally through a combination of aerobic and strength training exercises.

Where did the story come from?

The study was carried out by researchers from the University of Canberra and Australian National University, both in Australia. No funding information was provided.

It was published in the peer-reviewed British Journal of Sports Medicine on an open access basis, so it’s free to read online.

The study was widely reported, with somewhat conflicting and inaccurate advice in the headlines.

The Daily Telegraph and the Daily Express say people only need exercise for 45 minutes a week, although most of the studies included exercise programmes twice a week or more.

The intensity rather than the type of exercise was important, so moderate-intensity cycling should be as good as moderate-intensity walking or running.