Extra exercise in midlife could protect the brain in later life

People who do greater amounts of moderate-to-vigorously intense physical activity in middle age are less likely to show signs of brain damage 25 years later, a study has found.

Published: January 7, 2021 at 11:17 am

Brisk walking, running and biking in midlife may be linked to better brain health in later life, new research suggests.

The study, published in the journalNeurology, found that the more moderate-to-vigorous intensity physical activity people did from middle age through to later life, the less likely they were to develop brain damage 25 years later.

The results show that physical activity may have a protective effect on the brain, the researchers believe. Better brain health could reduce the risk of developing conditions such as dementia.

“Our study suggests that getting at least an hour and 15 minutes of moderate-to-vigorous intensity physical activity a week or more during midlife may be important throughout your lifetime for promoting brain health and preserving the actual structure of your brain," said Dr Priya Palta, Assistant Professor of Medical Science at Columbia University Irving Medical Centre in New York City.

“In particular, engaging in more than two and a half hours of physical activity per week in middle age was associated with fewer signs of brain disease.”

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The researchers asked the 1,604 participants to report their weekly amount of moderate-to-vigorous activity at the start of the study, and then twice more at later times. The researchers classified them as none, low, middle or high.

The participants had an average age of 53, and they attended five physical examinations over 25 years.

At the end of the study, the researchers looked for lesions, or areas of injury or disease in the participants' brains, and measured the participants' grey and white brain matter in brain scans.

After adjusting for demographics and lifestyle factors, people who reported no moderate-to-vigorous intensity physical activity in midlife were 47 per cent more likely to develop small areas of brain damage than people who reported high levels of moderate-to-vigorous intensity physical activity.

“Our results show that staying active during midlife may have real brain benefits," said Dr Palta.“In particular, consistently high levels of midlife moderate-to-vigorous intensity physical activity were associated with fewer brain lesions in later life.”

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But the study authors note that a limitation of the study is that it relied on participants reporting their own physical activity, which could be inaccurate.

Also researchers did not include physical activity other than leisure time activity – such as work-related or incidental activity.

“This research adds to a growing body of evidence suggesting exercise as an important way we can look after our brain health," said Dr Sara Imarisio, head of research at Alzheimer’s Research UK.

She added: “Just a third of people think it’s possible to reduce their risk of developing dementia, compared to 77 per cent who believe they can reduce their risk of heart disease.

“While there is no sure-fire risk way to prevent dementia, our brains don’t operate in isolation from the rest of our bodies and a good rule of thumb for everyone is that what is good for your heart is also good for your brain.

“The best current evidence suggests that as well as staying physically and mentally active, eating a healthy balanced diet, not smoking, drinking only within the recommended limits and keeping weight, cholesterol and blood pressure in check are all good ways to support a healthy brain as we age.”

Should I be worried if I don’t do 10,000 steps a day?

There’s no denying that walking is good for your health, but there’s nothing magic about the number 10,000. This figure is thought to have come from a Japanese pedometer called ‘manpo-kei’ (literally ‘10,000 steps meter’), marketed as a device for the health-conscious in the run-up to the 1964 Tokyo Olympics.

The 10,000 steps target has probably stuck around because it’s easy to measure and easy to remember. But a 2019 study led by researchers at the Harvard Medical School measured the step counts of almost 17,000 women over four years and found that the benefits tapered off well before 10,000 steps.

The least active women averaged about 2,700 steps per day, and increasing this to 4,400 steps was associated with a 40 per cent drop in mortality rates. Higher daily step counts showed greater benefits, but only up to 7,500 steps per day, at which point mortality rates levelled off.

This study only looked at older women (average age of 72), and there will have been many factors other than step count that affected their likelihood of dying within the four years. But the wider conclusion is that fixating on the number of steps isn’t necessarily helpful. A better – and perhaps more attainable – goal is 150 minutes of moderate exercise per week, including brisk walking.

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