The best evidenced thing for your thinking is not a brain game

Attention and memory

We have argued elsewhere on this site that brain training does not do what it is sold as doing. Which invites the obvious follow up: what does. The answer has no app behind it and rather more evidence. Move more.

Most articles stop at that line. It is actually where the argument begins, because the evidence linking exercise to thinking is at once the best we have and noticeably weaker than the confident way people tend to quote it.

Start with the part that is not in doubt

Go for a brisk walk and, for roughly twenty minutes to two hours afterwards, you will do slightly better on tasks that need attention and self control. By the standards of this field, that replicates well. The walk is the entire cost. Nobody has anything to sell you on the back of it.

It is also temporary, which is the bit the supplement adverts tend to omit. One session buys an afternoon, not a decade. Past that afternoon the researchers stop agreeing with each other.

The hippocampus study everyone quotes

Walking grows your brain, says most coverage of this topic. The source is a trial run by Kirk Erickson, in which 120 older adults spent a year either walking three times a week or doing stretching and toning instead. Anterior hippocampal volume went up by about 2% in the walkers and down by about 1.4% in the others, which is approximately what that part of the brain is otherwise expected to lose over a year or two at that age.

Staving off one to two years of shrinkage in a structure that sits at the centre of memory is a genuine result, and it has held up since. The headline then takes one further step and says the walkers remembered better. A letter in the same journal took issue with that step: the groups did not differ significantly on the memory measure, and within the walking group the change in volume did not track memory at all. The structure moved. Whether that changed anything a person would notice is a looser claim than the coverage lets on.

A brain region getting larger is a measurement of a brain region. Whether you would notice the difference is a separate question, and a harder one to answer.

Whether the kind of exercise matters

Here the evidence thins out, which is precisely what makes it interesting. Researchers separate open skill activities, where the surroundings keep shifting and you adapt as you go, from closed skill ones like running, swimming and cycling, where mostly they do not. A racket sport sits firmly at the open end.

One meta analysis pooled nineteen studies and found a small advantage for open skill activity on executive function, an effect size of about 0.17, biggest for cognitive flexibility and smallest for working memory. An effect that size is real but modest. Another meta analytic review found no significant difference between the two at all. This is a live argument, not a settled finding, and anyone presenting it as settled is selling something.

The longevity numbers, and what they cannot show

Peter Schnohr founded the Copenhagen City Heart Study, which tracked 8,577 people for as long as 25 years and weighed various sports against sitting still. Tennis came out on top at 9.7 extra years of life expectancy, with badminton on 6.2, football 4.7, cycling 3.7, swimming 3.4, jogging 3.2 and health club activity 1.5. The authors put the ordering down to the fact that the sports near the top of it involve another person.

It is a cohort study, so the caveat is the familiar one, and in this case a sizeable one. People who play tennis are unlike people who do not in money, free time, baseline health and the company they keep, and no statistical adjustment scrubs all of that out. The ordering is an association with a plausible story attached. It is not a receipt, and picking up a racket at forty does not come with 9.7 years attached to it.

What survives is still worth having: the sociable forms of exercise may carry something the solitary ones do not, and that something may matter as much as the aerobic part does.

What that leaves you with

Put the three strands side by side and they point one way, though no single one of them proves much on its own. Moving helps your attention today. It is associated with better outcomes across decades. And the versions involving other people keep coming out ahead, by a little in the laboratory measures and by a lot in the longevity data.

Which is the thoroughly unglamorous reason a padel court, or a five a side pitch, or a Tuesday night badminton league, is a more sensible purchase than a subscription to a training app. It is aerobic, it is unpredictable enough to count as open skill, and you cannot do it by yourself. A place like Courts Padel in West Berkshire puts the court next to the things people actually stay for, which sounds like a detail and is close to the whole problem. Adherence, not optimisation, decides whether any of this does anything. The best protocol you give up on in March loses to the mediocre one you are still doing in November.

None of this is medical advice, and we are not the people to ask for any. If something about your memory or your concentration is worrying you, take it to a qualified professional rather than to a quiz.