A recently-published study has provided strong evidence that regular exercise is very beneficial for the health and functioning of the brain in the over 50s. To many scientists, this is just confirming what we already knew. But for others, this may come as a surprise to hear.

Who can blame them? Crude portrayals and stereotypes from mainstream entertainment, most obviously bawdy American comedies of the 80s, give the impression there is some sort clear divide between enjoying physical or intellectual activities, as if these things are incompatible. They present a world where you can either be a big, lumbering, strong-but-monosyllabic sports star, or a feeble, pasty, asthmatic book-and-gadget-loving genius.

That’s if you’re a man of course. If you’re a woman you can either stand there and be lusted after, or mocked for not being attractive enough to be lusted after. What larks!

Reality, as ever, is nothing like that. The vast bulk of evidence suggests that, rather than there being a strict binary choice between working on your physical or mental abilities, the body and brain are in fact deeply interconnected. Admittedly, in the anatomical sense this is like saying there’s a clear link between a car and its engine. Duh! The brain is part of the body, it’s an internal organ.

That may be the case, but it’s also fair to say the brain is also something of a self-contained system of processes, with it and the rest of the body pursuing separate agendas in many ways. This is reflected in the way most people try to “improve” them. Lifting weights, running, rowing; physically demanding, cognitively very simple. Reading books, attending lectures, doing crosswords; cognitively stimulating, physically undemanding.

However, scientists have long contended that physical activity and brain functioning are fundamentally linked. There’s copious evidence out there which argues that increasing physical exercise doesn’t just make your body fitter and healthier, it also benefits the brain too, improving its functions and processes in a variety of interesting (and often surprising) ways.

Perhaps this shouldn’t be a surprise. The brain is, as has already been stated, an internal organ, and like any other organ it needs oxygen and nutrients and energy to survive, all the things it gets from the blood supply. Regular exercise can improve heart health, increase your metabolism, lower cholesterol (somehow), and numerous other things that boost the blood supply to your organs, including the brain. This would logically mean they have more resources to use, something particularly important for the incredibly-demanding brain, which could feasibly increase it’s activity and functioning when more “fuel” is available.

It may not be so indirect either; some evidence suggests that exercise prompts the release of BDNF (brain-derived neurotropic factor, a chemical that prompts growth of new neurons and connections). This would explain why exercise has such a prominent positive effect on the brain.

This isn’t to say it’s always been so obvious or clear-cut. Things to do with the brain seldom are. For instance, some studies have shown that children who do sports tend to do better at academic tests. A clear indication of the benefits of exercise on intellect? Or is it that smarter, more driven children are good at tests and into sport?

The age aspect is important too. Sure we might see exercise prompting improved brain function in young people, but they’re brains are technically still developing (and evidence suggests this carries on until the mid 20s), so maybe increased physical activity is just boosting that process? Maybe it isn’t the same for older people?

Thankfully, a very recent systematic review (a study which thoroughly analyses all the available studies and data relating to a specific subject or question) reveals that it is pretty much the same. Regular physical exercise also improves brain functioning in the over-50s too. This is important as that’s the age where cognitive decline can start to occur, and there’s a greatly increased risk of neurodegenerative diseases and dementia, particularly if physical health isn’t that good either. But now there’s hard data which indicates that regular exercise can keep the brain sharp and stave off a gradual loss of mental faculties. So that’s nice.

However, it’s important to keep conclusions like this in context. Yes, exercise may improve brain function, but it’s not an automatic guarantee. Many people in their physical prime struggle to operate anything more complicated than a pen, while Stephen Hawking is widely believed to have one of the most powerful brains on Earth despite being literally unable to engage in physical exercise. The factors that determine brain function and intelligence go way beyond how much exercise you get. It therefore doesn’t automatically follow that an overweight person is dumb by default, so don’t start attacking overweight people under that assumption, they get enough hassle as it is.

And that’s not even considering that increased physical activity like sports leads to a greater risk of head injury. Imagine that, doing all this work only to receive a head injury that impairs your brains functioning long term. What a pointless exercise.

Dean Burnett discusses other weird properties of our grey matter in his book The Idiot Brain, available in the UK, US and many other countries.