It’s official: frequent exercise gives you protection from dementia. After following more than 10,000 participants in their 50s for 16 years, researchers at the University of the Andes in Colombia determined that those who exercised regularly were 10 per cent less likely to have developed dementia by their 70s than those who had never exercised at all.

Scientists have suggested for years that there is a link between regular exercise and reduced dementia risk, but this latest study, published in September, was the first to track people over the course of decades to assess the impact that moving frequently can have.

Even better news is that the amount of exercise needed to reap these benefits is likely much lower than you think. “Anyone who exercised at least once or twice a week was found to have this reduction in risk,” says Dr Gary O’Donovan, the British researcher who led the study.

It was also found that “weekend warriors”, those who only exercise on Saturdays and Sundays, benefitted as much as people who exercised every day of the week. There was even some suggestion that they might have slightly more protection from dementia, “but there isn’t enough evidence to call it either way”, Dr O’Donovan says.

Another study recently carried out using UK Biobank data, which also followed people over years, was consistent with these recent findings in Colombia. “This is great news because if you can reproduce the results in two different countries, then that relationship is likely real,” Dr O’Donovan says.

The key message, he adds, is that some level of exercise is so much better for your brain than none at all, so people “should find an activity they enjoy and can stick to”. Here’s what the science says about how much exercise you need to do each week to stave off dementia – from sprinting and hardcore strength training, to walking and even yoga.

How it works

Simply put, “exercise is good for your brain health because it improves your brain chemistry, volume and function, all of which are linked to your risk of dementia in later life”, Dr O’Donovan explains.

Devi Sridhar, a professor of global public health at the University of Edinburgh and a Level 3 certified personal trainer, says: “When you exercise, your muscles release small proteins and other chemicals that travel to your brain and help maintain brain matter that tends to degrade with age.”

“This is something called brain-muscle crosstalk,” she explains, where the brain communicates with your muscles in a complicated way.

For this reason, even a short 30-second burst of activity, such as a brisk walk to the bus stop or a handful of sit ups, is better for your brain than a totally sedentary lifestyle.

At the same time, exercise increases the flow of blood and oxygen to your brain, helping it to retain its volume as you age. Regular exercise is also linked to improved mood and sleep, as well as lower blood pressure, and it helps you maintain a healthy weight. Stress, depression, a chronic lack of sleep and being overweight have all been shown to increase your dementia risk.

To get the full brain-boosting benefits that exercise can afford, it’s best to fit bigger chunks of movement into your week – though they needn’t be very long, or performed every day.

1. Aerobic exercise: An hour or two a week

The recent study from the University of the Andes only considered the impacts of aerobic exercise, which involves your body using oxygen to produce energy. Running, swimming, skipping and cycling are all forms of aerobic exercise.

Around half of the participants in the study who had a “weekend warrior” exercise style “said that they were doing so for 30 to 60 minutes, while the other half exercised in chunks of an hour or more”, explains Dr O’Donovan.

His team did not identify any difference between the dementia risk of people who responded in these ways, and they didn’t split up the “weekend warriors” into people who were exercising either once or twice a week.

On this basis then, an hour of jogging, swimming or riding your bike every week – split across at least two sessions – should be enough to lower your risk of developing dementia.

If you prefer to exercise in short bursts every day, however, 20 minutes a day is deemed a safer amount.