(Montreal) Low muscle mass is associated with faster cognitive decline in older adults, Montreal researchers have found.
Posted at 10:53 a.m.
This association is independent of factors such as muscle strength and level of physical activity. It would therefore seem that it is the muscle mass itself that is at stake, and that it is not a marker of more active seniors or having better lifestyle habits.
“With a measurement at the start and a measurement three years later, we see an overall cognitive decline (in the subjects), summarized the director of the study, researcher Stéphanie Chevalier from the Research Program in Metabolic Disorders and their Complications at the Research Institute of the McGill University Health Centre.
“But what we have seen is that in individuals with lower muscle mass, cognitive decline is more rapid. There was a greater decline over three years and it particularly affected executive cognitive functions. »
The researchers sifted through data from the Canadian Longitudinal Study on Aging, which has a large data set on body constitution and cognitive tests conducted in person three years apart in a cohort of 30,000 people.
They sought to determine whether low muscle mass could predict subsequent cognitive decline in three domains — memory, executive function and psychomotor speed — in adults aged 65 and older.
An association was found between low muscle mass and greater decline in executive function over a three-year period compared to having normal muscle mass, but no such association was seen in regarding memory and psychomotor speed.
Executive functions are crucial in everyday life, as they help sustain our attention, organize our thoughts and make decisions.
“I wasn’t entirely surprised to find a basic relationship between low muscle mass and cognitive decline, because those are two aspects of functionality,” Ms.me Knight.
“What surprised me was that once we adjusted the link between muscle mass and cognitive decline to sort of remove the impact of physical activity, there was even a link. This means that muscle mass as such has an association independent of other factors with cognitive decline. There, I was a little surprised. »
The physiological factors that could explain how increased muscle mass slows cognitive decline remain mysterious. We know, however, that muscles secrete molecules that can have an anti-inflammatory effect and that these molecules are secreted more by the muscle in action.
It is also known that physical exercise and the development of muscle mass, by providing increased blood flow to the brain, can promote executive functions.
The good news, the researchers point out, is that muscle mass is a modifiable factor. The youngest can begin to build reserves for their old age, and even for the elders, it is never too late to do well.
“There are great studies that have been done with centenarians who have shown that with physical exercise […]it is possible to regain muscle, recalled Mme Knight. And you don’t have to take protein supplements. A good diet that contains enough good quality protein, combined with exercise, are certainly the two main factors that will help us maintain muscle mass. »
The findings of this study are published by the medical journal JAMA Network Open.