25 minutes of moderate exercise weekly can help prevent cognitive decline

Doing moderate exercise for 25 minutes a week (that is, the equivalent of less than four minutes per day) could be a valid strategy to strengthen the brain and help prevent cognitive decline.

That is the conclusion of a recent study published in the scientific journal

Journal of Alzheimer's Disease,

in which brain MRI was performed on more than 10,000 healthy men and women between 18 and 97 years old.

The researchers found that, regardless of age, those participants who exercised moderately for at least 25 minutes a week had larger brain volumes in areas related to thinking and memory that tend to lose volume as we age.

“The process of age-related brain volume loss appears relatively unique to humans.

It is estimated that it begins with a volume loss of 0.2% per year in the 30s and increases to 0.5% per year by age 60, increasing to 4% per year in Alzheimer's.

With age-related loss of brain volume comes a loss of cognitive efficiency.

Taking into account that we do not have drugs to prevent this deterioration, the results of this study are important,” explains Cyrus A. Raji, professor at the Washington University School of Medicine (St. Louis, United States).

The main author of the study considers that the data are “surprising” due to the low threshold of physical activity necessary to achieve a beneficial impact on brain health: “current public health recommendations suggested 150 minutes per week of moderate physical activity;

"However, our study is encouraging because lower thresholds of physical activity, which are easier for more people to achieve, may still carry potential benefits for brain health."

Lower physical activity thresholds, which are easier for more people to reach, may still carry potential brain health benefits

Cyrus A. Raji, professor, Washington University School of Medicine

For Jesús Porta Etessam, president of the Spanish Society of Neurology (SEN), the data from the study “reinforce all previous findings and all hypotheses regarding that moderate and sustained physical exercise can be a factor that prevents cognitive deterioration” .

The neurologist at the San Carlos Clinical Hospital considers that the increase in brain volume associated with physical exercise could be due to a greater number of synaptogenesis: “An important thing about the study is that it is not seen that the participants who exercise remain the same, while In the rest, the brain is atrophying, but in the first the brain volume increases,” he adds.

Juan Domingo Gispert, head of the Neuroimaging group at the Barcelonaβeta Brain Research Center (BBRC) of the Pasqual Maragall Foundation, for his part, points out that the research data “are plausible”, but considers that this type of association studies are subject to multiple interpretations: “You may think that exercise causes greater brain volume, but you could also think the other way around.

That is to say, people who have a better preserved brain have an easier time doing physical exercise because they are in better health, so the direction of causality would be the opposite.

The most robust conclusions are obtained from clinical trials, of which approximately a dozen have been published.”

One of them was carried out in 2021 by researchers from the Institute of Neurosciences of the University of Barcelona in research published in

Frontiers in Aging Neuroscience

.

In this case, the conclusion was the same: “Our results show that exercise is a promising approach to influence inflammation and brain volume.”

Physical exercise and Alzheimer's

According to data from the Pasqual Maragall Foundation, it is estimated that dementia affects one in ten people over 65 years of age and a third of those over 85. In total, around 900,000 people suffer from dementia in Spain, being the most common cause. Alzheimer's is common, which can account for between six and seven out of every ten cases.

"While we are waiting for lecanemab and donanemab to arrive, the first drugs that have shown some effectiveness in modifying the progression of Alzheimer's, there is no medication that prevents mild cognitive impairment in patients, but we do have measures that can delay This cognitive deterioration associated with a neurodegenerative disease and one of them, along with the Mediterranean diet, an active social life, or mental health care, is moderate and continuous physical exercise over time.

So, if we are told that 25 minutes a week can increase brain volume and, therefore, theoretically reduce the future risk of cognitive decline, it costs nothing to climb the four flights to the office or walk instead of taking a bus. taxi.”, says Porta Etessam.

More information

The risk of suffering from dementia can be prevented by improving lifestyle habits

Could physical exercise then be a kind of preventive medicine against Alzheimer's?

“The fact that, according to our research, the improved regions include those important for the development of the disease suggests that physical activity may be an important way to maintain brain health and reduce the risk of memory loss in the future.” ” replies Cyrus A. Raji.

An opinion that is not entirely shared by Juan Domingo Gispert, who has no doubts about the impact of exercise at a cardiovascular level, but at a more molecular and Alzheimer's specific level.

“Physical exercise is recognized as a protective factor against dementia, but what is not very clear is what the mechanism is.

Surely this is more about improving cardiovascular health.

The most prevalent dementia is Alzheimer's and the risk factors that prevent up to a third of cases are, for the most part, of cardiovascular origin (hypertension, hypercholesterolemia, sedentary lifestyle, etc.)", maintains the spokesperson for the Barcelonaβeta Brain Research Center. .

A recent study published in

The Lancet Healthy Longevity

by researchers at the National Center for Cardiovascular Research (CNIC) and headed by Gispert himself, in fact, has just shown that atherosclerosis (the accumulation of fatty deposits in the arteries), in addition to Being the main cause of cardiovascular disease, it is also involved in the brain alterations typical of patients with Alzheimer's, which could mean that asymptomatic people with atherosclerosis would be more vulnerable to the effects of this disease.

Juan Domingo Gispert recalls that Alzheimer's is characterized by the accumulation in the brain of the tau protein and the amyloid beta peptide 42. In 2023, a group of Spanish researchers published a systematic review of studies that have delved into the relationship between physical exercise and amyloid beta protein.

The result?

Physical performance was not associated with amyloid beta accumulation in the brain or blood.

“There is no conclusive data, it would be plausible to think that physical exercise can serve in a very early stage of the disease, helping to prevent amyloid from accumulating in the brain (this happens up to 20 years before symptoms appear).

There, when protein begins to accumulate, is surely when physical exercise can have a greater impact on that accumulation,” Gispert concludes.

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