Aging changes the brain, shrinking parts of it and affecting memory and thinking even in healthy older adults.
But slowing down this process could be as simple as regularly taking a walk, gardening or dancing. Such leisure time physical activity may slow brain aging by up to four years, researchers at Columbia University in New York reported Thursday.
The preliminary findings, based on brain scans of hundreds of older people, will be presented at the American Academy of Neurology’s annual meeting next month. It’s the latest in a growing body of research showing how good exercise can be for the mind.
“Usually people think physical activity is beneficial for cardiovascular disease, for your heart. Now we think it’s also possibly beneficial for the brain,” Dr. Yian Gu, lead author of the study and assistant professor of neurological sciences at Columbia University, told TODAY.
“On average, people who are more active have larger brains.”
That’s a good thing because researchers believe people reach peak brain volume in their 20s. Then, the brain starts to shrink — slowly at first, but accelerating after middle age, Gu said.
“It’s just general aging, like your skin,” she explained. But exercise appears to put a brake on the brain shrinkage in older age. More physical activity was associated with larger brain volume in the elderly, the study found.
The exact biological mechanisms for this effect are still a mystery, Gu noted.
The cross-sectional study involved 1,557 adults who were 75 years old on average. All were part of the Washington Heights-Hamilton Heights-Inwood Community Aging Project, a study of elderly, urban-dwelling people that began in 1989.
The participants self-reported the amount of time they spent engaging in physical activity in the past two weeks and were divided into three groups: most active, least active and the group in between.
Researchers later scanned their brains using MRI.
It turned out the people in the most active group had a larger total brain volume, gray matter volume and white matter volume than those in the least active group, even after adjusting for age, sex and other factors.
The effect was equivalent to three to four fewer years of brain aging. The study doesn't prove exercise prevents brain shrinkage, but it shows an association.
"We have been telling patients for years that mental and physical activity is good for them and is a good 'treatment' for dementia. This study validates this recommendation with improved brain size," said Dr. Thomas Vidic, a neurologist in Elkhart, Indiana. He was not involved in the new research.
Gray matter contains neurons, which transmit information. White matter contains their extensions, nerve fibers known as axons. "Both parts are very important and both parts can shrink when people get older," Gu said. So the bigger the volume, the better.
In the study, the people who were most physically active engaged in one of these activity patterns each week:
- Either seven hours of low-intensity physical activity, such as walking, dancing, bowling or gardening
- Or four hours of moderate physical activity, such as swimming, hiking or playing tennis
- Or two hours of high-intensity physical activity, such as jogging
Gu said it’s best to become active as early as possible in life to promote brain health, but she urged caution before jumping into an exercise routine.
“I want to make sure people don’t go crazy about it. They have to think about their own underlying health condition,” she advised.
In other words: Check with your doctor before starting a new workout and know your limits.
Gu wants to conduct a longitudinal study to confirm the results in the future.
Previous studies have found exercise can take 10 years off a brain's age, though it needed to be moderate physical activity, so walking, golf, bowling and yoga didn’t seem to count.
Exercise was also a better brain workout than puzzles for older people, another study found.
Separate research found physical activity improved thinking skills — including memory, alertness and the ability to quickly process information — in people over 50. The key was 45-60 minutes of moderate to vigorous exercise per session “on as many days of the week as feasible.”