Regular aerobic exercise sharpens your memory — and now we know why

Exercise has long been thought to improve memory — now scientists have found at least part of the reason why.

Researchers have discovered that aerobic exercise raises levels of a protein, called cathepsin B, which accelerates cell growth in a part of the brain critical to memory.

The study, published in Cell Metabolism, tested the connection in mice, monkeys and then humans.

The human study involved 43 ‘couch potato’ university students. Half of them remained sedentary while the other half ran on treadmills several times a week.

The students who exercised saw their levels of cathepsin B rise as they got fitter and they performed better at a memory task. The students with the largest rise in cathepsin B also showed the most dramatic improvement in memory.

Dr Henriette van Praag, a neuroscientist at the National Institute on Ageing in the United States, told the Daily Telegraph: ‘People often ask us, how long do you have to exercise, how many hours? The study supports that the more substantial changes occur with the maintenance of a long-term exercise regimen.’

She added: ‘I don’t think we have fully explained how exercise improves memory. But I think we’ve made a significant step forward.’

Instant analysis
We have known for many years that exercise is good for us in many ways, including helping with memory and learning, but without really knowing why. This study brings us one step closer to answering this question. The numbers in the human trial are small, however, and it is likely to be viewed as an observational study rather than ground-breaking research. However, what it does show is that the consistent advice we give people that exercise is good for them remains clear, and that a long-term exercise regimen is probably best for its widespread benefits rather than short or intermittent bursts of activity.
Research score: 3/5