by University of Copenhagen

Parameter inference workflow proposed and microbiome data properties. Credit: Aging Cell (2024). DOI: 10.1111/acel.14413

We all know that exercise is the answer to just about everything. But did you know that you don't have to exercise like a maniac every day to reap some of the benefits?

New research from the University of Copenhagen and Bispebjerg Hospital published in Aging Cell shows that regular fitness training and physical exercise such as playing football with your friends, going to the gym or cycling to work protects the muscle cells and the so-called motor neurons. And this will affect your health in old age.

This is good news if you don't like the prospect of crammed gyms, CrossFit classes or three weekly boxing sessions, says Postdoc Casper Søndenbroe from the Center for Healthy Aging at the University of Copenhagen and the Institute of Sports Medicine at Bispebjerg Hospital.

"Motor neurons are the nerve cells that allow us to move. They are severely affected by diseases such as ALS (amyotrophic lateral sclerosis). However, as we age, the motor neurons also degenerate and die, and that is why we are so keen to find out how we can best protect the motor neurons," he explains.

"Our study suggests that even moderate, regular exercise has a protective effect on the muscles and motor neurons far into old age. And it can be anything from playing paddle tennis or football with your friends a couple of times a week, doing weight training or taking long cycle rides. The important thing is to continue to be physically active," says Søndenbroe.

Cycle rides make a difference

The researchers compared cells from muscle biopsies from nine young persons and muscle biopsies from 13 senior citizens. The latter group was divided into two subgroups: those who had been physically active for many years, and those who had not.

The subjects in the active subgroup had varied—and thus very realistic—exercise patterns. Some of the subjects may have played football for a while, before stopping and starting jogging, while others had practiced weight training, athletics or something else entirely.

In other words, their exercise pattern very much resembled that of most Danes.

"You can help your body work well for longer. On average, people lose 2% to 3% of their muscular power per year from age 60, which is related to a deterioration of the muscle cell and motor neuron interaction. This is where exercise can make a difference," says Søndenbroe.

The study, which is the first of its kind, shows that exercise has a protective effect on the muscle cells and the motor neuron they interact with.

This is because the ability of the muscles to contract depends on interaction between the muscle cells and the motor neurons. In the study, the researchers therefore made human muscle cells interact with motor cells from rats. And they found that the two cell cultures contracted—just like our muscles do.

The next step was to determine how long the motor neurons lived and compare the muscle cells of the younger and older subjects as well as the active and non-active subgroups. There was a clear difference here.

It is never too late to start

The results suggest that if you want to remain healthy for as long as possible, you have to start exercising before you have lost too many motor neurons.

Still, there is hope, Søndenbroe explains. "Even if you start doing weight training at age 80, you will still be able to improve interaction between the muscles and neurons, and thereby get stronger," he says.

The study also identified a new role of the cell type known as fibroblasts. And even though communication of this part of the research is limited, it may still influence future studies of muscle-nerve interaction.

"Fibroblasts, which is a type of cell that contributes to the formation of connective tissue, have a somewhat tarnished reputation. In short, you don't want to have too many fibroblasts in the 'wrong areas.' But in this study, we found that the fibroblasts—just like the muscle cells—had a positive effect on the motor neurons. And that surprised us."

More information: Casper Soendenbroe et al, Muscle fibroblasts and stem cells stimulate motor neurons in an age and exercise‐dependent manner, Aging Cell (2024). DOI: 10.1111/acel.14413

Journal information: Aging Cell 

Provided by University of Copenhagen