Use it or lose it

Evidence is growing that regular exercise improves not just physical health but brain function and mental wellbeing. And we don't have to become gym bunnies to benefit.

- RUTH NICHOL

Unlike our closest relatives among the great apes, we can’t get away with spending our days lazing about doing nothing more strenuous than plucking the occasional piece of fruit from a tree.

We may share 99% of our DNA with them, but animals such as gorillas and chimpanzees can spend up to 20 hours a day resting, eating, grooming and sleeping without getting fat or suffering any of the health problems that plague modern humans, such as heart disease and diabetes.

Nor do they experience much in the way of anxiety or depression – at least when they’re living in the wild.

As much as we would like to loll about in a similar fashion – and we have used our superior brains to engineer our lives so that most adults now spend 70% of their time either sitting or lying down – we’re paying the price in terms of poor physical health and an epidemic of mental illness.

“We’re now at a point where we can order food, we can date, we can entertain ourselves without having to move a muscle – we don’t even have to get up to change the channel on the television anymore,” says British science writer Caroline Williams.

In her recent book, Move! The new science of body over mind, she says our increasingly sedentary lifestyle means that as well as declining physical and mental health, we’re also weaker than we used to be. An American study of students aged 20-35 published in 2016 found that men’s grip strength had fallen over three decades, with Millennial males able to exert just 44.5kg of force compared with the 53kg their fathers could exert in the same test in 1985.

That in itself is likely to be a contributing factor to growing levels of mental ill health.