“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 Sun says “walking benefits the brain more than cycling” – but the study didn’t present any evidence for this.
The intensity rather than the type of exercise was important, so moderate-intensity cycling should be as good as moderate-intensity walking or running.

What kind of research was this?

This was a systematic review and meta-analysis of randomised controlled trials (RCTs) of exercise programmes.
A meta-analysis of RCTs is a good way to summarise and pool evidence to show whether a particular intervention (in this case, exercise) affects a particular outcome (in this case, cognitive function).
What did the research involve?

Researchers looked for any RCTs that compared an exercise programme with a control group, among adults over 50 living at home, with at least one test of cognitive function (mental ability) as an outcome.

They excluded studies where exercise was not the only intervention – for example, exercise plus brain training – to focus the study on exercise alone.

They then pooled the results between exercise groups and control groups to find the standard mean difference from baseline cognitive function.

Researchers also analysed the results by:
type of exercise (aerobic, resistance/strength training, a combination of the two, yoga and tai chi)
intensity (low, moderate or high)
duration of exercise session (less than 45 minutes, 45 minutes to an hour, more than an hour)
length of programme (4-12 weeks, 13-26 weeks, more than 26 weeks)
frequency of exercise sessions (two or fewer, 3 or 4, 5-7)
Tests of cognitive function included overall cognition, attention (such as ability to process information quickly), executive function, long-term memory, and short-term working memory.

All the studies were assessed for risk of biases, such as publication bias. The researchers did not exclude any studies based on the date of publication or type of exercise.

For the full articles please visit the NHS Choices website