Studies show that physical exercise helps prevent dementia

Experts have long believed that exercise could help protect people from developing dementia. However, while they have observed an overall pattern of risk reduction, studies on the subject have been small and often conflicting, with little consensus on what type, frequency, or intensity of exercise would be best.

“There is no clear prescription for physical activity that we can provide,” said Joel Salinas, an assistant professor of neurology at New York University’s Grossman School of Medicine who specializes in treating people with dementia.

But three large, long-term studies released in recent months have attempted to characterize the types, intensities and durations of physical activity that provide the greatest overall protection against dementia. These studies, which have followed thousands and even hundreds of thousands of people for years, confirm that regular physical activity, in many ways, plays a substantial role in lowering the risk of developing dementia.

Vigorous exercise seems to be the best, but even non-traditional exercise like housework can offer a significant benefit. And surprisingly, it is equally effective at reducing risk in people with a family history of dementia.

Many forms of exercise can prevent dementia

In the first study, published July 27 in the journal Neurology, researchers analyzed the health information of 501,376 participants who did not suffer from dementia, from a British database called the UK Biobank, to establish links between physical activity and the risk of developing dementia. the disease.

One of the main advantages of this database was that it had “very elaborate data on the genetics” of the participants, said one of the study’s authors, Huan Song, a researcher at the West China Hospital at Sichuan University.

This included a risk profile of participants based on whether they had genetic variants commonly associated with dementia or had immediate relatives with the disease.

At the start of the study, participants filled out detailed questionnaires about their physical activities, such as playing sports, climbing stairs or walking, and whether they regularly walked or cycled to work. They were also asked about various lifestyle factors, including how often they performed household chores.

One of the main limitations of previous studies was that “the definition of physical activity is pretty weak,” Song said. “Some use the full amount and some just focus on one activity mode.” The British questionnaires offered specificity about exactly what activities participants regularly engaged in.

Participants were followed for 11 years, in which 5,185 of them developed dementia. The study found that in participants who engaged in regular, vigorous activities such as sports or strength training, the risk of developing dementia was reduced by 35%.

Surprisingly, people who reported doing household chores regularly also experienced a significant benefit: they had a 21% lower risk.

“Some people sweat a lot when doing housework,” said Sandra Weintraub, a neurologist at Northwestern University’s Feinberg School of Medicine who was not involved in this study. “It could be that if you do three hours of chores, it’s as good as doing 30 minutes of cardio.”

For Salinas, who recommends that people get 150 minutes of moderate-to-high-intensity exercise a week, the results reinforce the idea that regular moderate to vigorous exercise can promote brain health.

Cultivating this exercise habit “is likely to have a very profound synergistic effect,” he said. “You get a lot more in terms of helping to promote your own health through physical activity.”

Perhaps most encouragingly, the association between physical activity and lower risk of dementia included participants who had a family history of the disease.

“It’s very important to know that if you have a family history of dementia, you can use physical activity to reduce your risk,” Song said.

Start doing what you love

The second paper, published in early August in Neurology, compiled 38 studies to see which leisure activities were associated with a reduced risk of dementia. In all, the studies followed more than 2 million participants without dementia for at least three years, during which 74,700 developed the condition.

After controlling for age, education and sex, the researchers found that participants who exercised regularly — activities such as walking, running, swimming, dancing, playing sports or working out in the gym — had a 17% lower risk of developing dementia compared with those who exercised regularly. who didn’t exercise.

This meta-analysis shows that dementia prevention is not limited to one activity, or even one type of activity. Given the diversity of physical activities the participants engaged in, “we recommend people do the exercise they enjoy,” said Le Shi, a researcher at Peking University and one of the study’s authors.

When it comes to reaping the benefits of physical activity, it’s never too early to start. In a third study published this month, researchers followed more than 1,200 children ages 7 to 15 for more than 30 years.

Those who had higher levels of fitness as children had higher levels of cognitive functioning in middle age, suggesting that establishing a lifelong habit of physical activity can be beneficial for brain health.

Together, these studies suggest that the ways we move our bodies on a daily basis can add up over time. They also solidify the notion that regular, lifelong physical activity, in all its forms, goes a long way toward reducing the risk of dementia, even for people classified as high risk.

“Your brain is part of your body and will benefit from anything you do that is good for your overall health,” said Weintraub.

Translated by Luiz Roberto M. Gonçalves