Wellness Check

Study Reveals Why Exercise is so Good for the Brain

Jun 2024 | By David Cravit and Larry Wolf

It’s no secret that regular exercise is great for the body and the brain. Scientific studies have shown, time and time again, that physical activity has both short and long-term cognitive benefits, from boosting memory and concentration in the hours following a gym session, to reducing inflammation and mitigating risk of progressive, degenerative diseases like Alzheimer’s.

New research sheds light on one potential mechanism for exactly how exercise aids in brain health. A study published in the journal Proceedings of the National Academy of Sciences shows that when muscles contain more nerve cells, and when those muscle-stimulating nerve cells are active, muscle tissue produces a bevy of brain-boosting compounds.

Muscles all around our bodies are connected to the brain through a network of nerve cells that penetrate into the muscle tissue, creating “innervated muscle.” Past studies have shown that strength and resistance training can increase the level of muscle innervation, bolstering that brain-body connection. Other complementary research has demonstrated links between loss of innervated muscle and organ impairments and cognitive dysfunction. The new work goes one step further, showing that innervated muscle is important for the production and transport of many molecules that support and improve brain function, including proteins, mRNA, and hormones.

Lead author Hyunjoon Kong, a professor of biomolecular engineering at the University of Illinois Urbana-Champaign, told Medical News Today that the study didn’t directly prove that exercise can improve cognitive function, but it did show that exercise enables muscles to maintain the neuron connections necessary for muscles to help the brain.

“With regular muscle contractions, muscles not only secrete these beneficial factors, but also help sustain the innervation necessary for nerves to continue signaling muscles,” he said to MNT. The findings suggest a communication feedback loop wherein exercise prompts nerve cells to grow stronger connections with muscle cells, which supports brain health, which helps maintain more muscle innervation.

“It’s our individual organs talking to each other: The brain tells the nerves to stimulate the muscle, and the muscle releases back molecules beneficial for brain function,” Kong said in a university press statement.

Kong and his co-researchers came to their findings by creating a model system of innervated and non-innervated muscle cells, grown on a plastic medium. They stimulated these muscle models with the neurotransmitter glutamate, compared their activity, and analyzed the compounds produced by cells in each condition. They found that innervated cells made more brain-boosting substances and that production of those beneficial biochemicals went up even more with glutamate stimulation – mimicking muscle movement.

The study researchers further exposed neurons to the biomolecular soup created by their synthetic innervated muscle tissue and found increased neural growth, compared with neurons steeped in the products of the nerve-free muscle tissue.

More research is needed to see if these effects hold up in the human body, and not just in synthetic models, to test if exercise can really boost lost muscle innervation and brain health, and to compare the effects of different types of exercise. But, for now, add brain-boosting biological soup to your list of reasons to stay moving.