posted on 04/14/2022 06:00
It has been known for some time that exercise helps protect the brain from the damage associated with aging. Now, a study published in the journal Neurology, of the North American Academy of Neurology, points out the mechanisms involved in this relationship. The article, from the Inserm Research Center in France, suggests that, by helping to maintain insulin levels and promoting a healthy body mass index (BMI), physical activities act as a brain shield, preventing shrinkage of the organ’s volume. Thus, they help to avoid or delay dementia.
“These results may help us understand how physical activity affects brain health, which will guide us in developing strategies to prevent or delay age-related decline in memory and cognitive skills,” said lead author Géraldine Poisnel. . “Older adults who are physically active gain cardiovascular benefits, which may also result in greater brain structural integrity.” In contrast, the researchers found that the relationship between exercise and organ glucose metabolism was not affected by insulin levels or BMI. This decrease can be seen in people with dementia.
The study involved 134 people with an average age of 69 years, who had no memory problems. They answered questionnaires about the level of physical activity practiced in the year prior to the survey, in addition to undergoing brain imaging tests to measure organ volume and glucose metabolism. Information was also collected on BMI and insulin rates, as well as cholesterol and blood pressure, among other factors.
People who exercised more had a greater total volume of gray matter in their brains than those who reported less exercise, averaging about 550,000 cubic millimeters compared to 540,000. When the researchers looked at just the areas affected by Alzheimer’s disease, they found the same results. Those who exercised more often also had higher average rates of glucose metabolism.
A higher level of physical activity, however, was not associated with the amount of amyloid plaques in the brain. These fatty deposits are a marker of Alzheimer’s, points out Poisnel. According to her, although the relationship between exercise and brain volume robustness has been noticed in this and other studies, more research is needed for a detailed understanding of the mechanisms involved. Still, the scientist explains that the work shed more light on the topic. “Maintaining a lower BMI through physical activity can help prevent disturbances in insulin metabolism that are often seen in aging, thereby promoting brain health,” she said.
Another research published yesterday in The British Medical Journal also reinforced the protective role of a healthy lifestyle against brain aging. According to the study, in addition to a longer life expectancy, habits such as physical activities, a diet low in animal fat and cognitive stimuli also help to live longer and without dementia.
The number of people living with Alzheimer’s and other neurodegenerative diseases is expected to triple worldwide by 2050, from about 57 million in 2019 to 152 million in 2050, according to the World Health Organization (WHO). One of the risk factors for dementia is advanced age. Thus, living longer could mean an increase in years spent with cognitive impairment, a little explored issue that motivated the study, conducted by US and Swiss scientists.
The research analyzes data from 2,449 participants aged 65 and over (mean age 76) with no history of dementia, whose data are available from a large epidemiological study, the Chicago Health and Aging Project. Volunteers completed detailed diet and lifestyle questionnaires. The researchers developed a score considering a Mediterranean-Dash hybrid diet (rich in whole grains, green leafy vegetables and berries, and low in fast/fried foods and red meats); cognitively stimulating activities (reading, visiting a museum or doing crossword puzzles); at least 150 minutes per week of physical exercise; not smoking, and low to moderate alcohol consumption.
For each factor, participants were given a score of one if they met the criteria for healthy, and of zero if they didn’t. The variables were added together to produce a result that could be as high as five. Higher points indicated a healthier lifestyle, according to what scientists considered.
Implications for public policies
After taking into account other potentially influential factors, including age, gender, ethnicity, and education, the researchers from Switzerland and the United States found that, on average, the total life expectancy at age 65 in women and men with a healthy lifestyle was 24.2 and 23.1 years, respectively. But for female and male participants with more unhealthy habits, longevity was lower: 21.1 and 17.4 years, respectively.
Among healthy lifestyle women and men, 10.8% and 6.1% lived with Alzheimer’s for 2.6 and 1.4 years, respectively. This time was longer in participants who had habits considered bad: 19.3% of the volunteers spent 4.1 years with the degenerative disorder, and 12% of the volunteers lived 2.1 years with the problem. At 85, these differences were even more noticeable, the scientists said.
Although it used population data with long-term follow-up, the research is observational; therefore, it does not establish a cause and effect relationship. However, the researchers conclude: “This research suggests that an extended life expectancy due to a healthy lifestyle is not accompanied by an increase in the number of years living with Alzheimer’s.”
In an editorial associated with the article and published in The British Medical Journal, University of Michigan researcher HwaJung Choi highlights the “important implications for the well-being of aging populations and for related public health policies and programs.” argues that the development and implementation of interventions to reduce the risk of dementia is “extremely important” in global efforts to ease the pressure on health systems. “Promoting healthy lifestyles can increase dementia-free years by delaying the onset of neurodegeneration,” she concludes.