A belief that keeping the body in shape is good for the mind goes back to the dawn of medicine. The phrase mens sana in corpore sano comes from Ancient Rome. Today, scientists hail working out as a ‘miracle pill’ not just for the body but also for the brain. As an article on the Harvard Medical School blog put it: ‘Aerobic exercise is the key for your head, just as it is for your heart.’

That is why staying active is woven into the routines of so many creative people. Steve Jobs was an avid walker. Bowie stayed in shape by boxing. A keen sportsman in his youth, Mac takes a brisk walk round the park every day and regu- larly plays golf. He breaks sweat at a daily dance class.

No one is sure why exercising is so good for the brain. One theory is it delivers an energy-and-oxygen boost by increasing the flow of blood. Another is that it fires up the body’s metabolism, which in turn fuels neural growth. What is clear from many studies is that regular aerobic exercise can help keep us cognitively fit. For example, working out has been shown to stimulate the growth of white and grey matter in the frontal and temporal lobes and plump up the hippocampus by creating new brain cells – just like study- ing for The Knowledge. ‘It is very impressive how much the functioning of our brain is impacted by physical exercise,’ says Ursula Staudinger, founding director of the Robert N. Butler Columbia Aging Center in New York.

How much exercise is needed to enjoy this cognitive dividend? Once again, you don’t have to take up extreme sports or run marathons. Experts recommend about 45 minutes of moderate exercise – cycling, swimming, jogging or even just an energetic walk – at least three times a week seems to do the trick. That is not far off the recipe for keeping the body fit, which means you can kill two birds with one stone. And, though the younger you start the better, it is never too late to reap the rewards: even people who take up exercise in their 60s, 70s and 80s notice improvements in cognitive function after three months and lasting neural changes after six.

Exercise may even help with what might be the most wor- rying cognitive cloud hanging over the longevity revolution: dementia. Today, around 50 million people suffer from the condition, with that number expected to hit 75 million by 2030. Dementia is now the leading cause of death among women in England, Wales and Australia and may affect 70 per cent of people in the world’s care homes. Not only is there no cure but we do not even know why it strikes in the first place. Nevertheless, the picture is not as apocalyptic as the headlines proclaim. While more likely to strike in later life, dementia is not – repeat, it is not – an inevitable part of ageing. Around 17 per cent of people over the age of 80 have it, but that means the other 83 per cent do not. What’s more, the latest data suggests the average age at which dementia strikes is rising and the percentage of the population affected at every age is falling. Experts put this down to more of us following the best-guess advice on how to keep our brains in good working order: eating more healthily, smoking and drinking less, exercising body and mind. With money and manpower now pouring into the study of dementia, longi- tudinal studies already underway could yield personalised prevention and treatment plans within a decade. As director of the Centre for Dementia Prevention at the University of Edinburgh, Craig Ritchie is on the cutting edge of research into the disease. He believes we are on our way to figuring out how to prevent dementia through drugs and lifestyle changes. ‘In 10 or 15 years we’ll be able to say “this is your risk and you can do this, this and this to reduce it – or maybe even eliminate it altogether,” he says. ‘I’m hugely optimistic about the future.’

The race to defeat dementia might even help unlock the secrets of creativity. Some people find that coming down with the disease makes them much more creative. No one knows why this happens, but one theory is that shutting down certain parts of the brain causes others to flow and fire more freely. That is not, of course, a reason to try to get dementia, but it is a reminder that the brain is a remarkably pliable and resilient organ with plenty of creative juice.

If we treat that organ right, most of us can look forward to creating, innovating and learning throughout our longer lives. We could also spark a revolution in the workplace.

Excerpted from Bolder: Making the Most of Our Longer Lives by Carl Honoré. Copyright © 2018 Carl Honoré. Published by Alfred A. Knopf Canada, a division of Penguin Random House Canada Limited. Reproduced by arrangement with the Publisher. All rights reserved.

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