Study Shows Muscle Contraction During Exercise Can Help Heal Nerves

We know that exercise has impressive physical and mental health benefits. There’s clear evidence that physical activity can positively affect the structure and function of various body tissues, including muscles, bones, fat, blood vessels, immune cells, and the central and peripheral nervous systems.¹

But exactly how exercise exerts positive effects at the cellular level was not well understood… until now.

A recent study done at the Massachusetts Institute of Technology analyzed how muscle contractions during exercise can influence the growth and function of brain cells or neurons.

But first, let’s take a closer look at the relationship between muscle cells and neurons.

Jump to:

• The Relationship Between Muscle Cells and Brain Cells
• The Study
• The Results
• Practical Implications

The Relationship Between Muscle Cells & Brain Cells  

Neurons are important when thinking about how the body moves because skeletal muscle cells and motor neurons work together to coordinate all intentional movement.

Motor neurons, a type of nerve cell, send signals from the brain and spinal cord to skeletal muscle cells, triggering them to contract and produce movement.

This connection occurs at specialized sites called neuromuscular junctions, where chemical signals from neurons are converted into electrical and mechanical responses in the muscle.

Beyond this functional link, skeletal muscles and neurons also communicate through biochemical signals, influencing each other's growth, repair, and overall health.

Previous research has suggested that muscle contractions may help motor neurons grow. However, in the past, studying this in living organisms has been complex, which leads us to a new study…

The Study

In a recent study titled “Actuating Extracellular Matrices Decouple the Mechanical and Biochemical Effects of Muscle Contraction on Motor Neurons”, published in Advanced Healthcare Materials, researchers analyzed how muscular contractions during exercise can impact neurons.

In their analysis, the research team used an animal model, studying mice. Past studies on how muscle contractions can influence neurons were done in vivo, meaning within a living organism.

However, to gain more detail on how exactly this process works and the differences between the biochemical (chemicals released during muscle contraction) and mechanical impact (physical stretching of neurons that occurs during exercise), the researchers carried out an in vitro study, i.e. in a laboratory setting.

To accomplish this, the team developed a way to create stable layers of contracting muscle cells using a specially tuned fibrin hydrogel that mimics the extracellular matrix.

When muscles contract during exercise, they release molecules called myokines. The muscle layers allowed the team to collect these proteins and molecules secreted by exercising muscles over time.

Additionally, using magnets, the team applied mechanical forces to motor neurons, mimicking the stretching that happens during muscle contractions. The researchers did this to see if exercise impacts the neurons on this physical and mechanical level. 

The Results

The results of the study showed that when neurons were exposed to molecules released by the muscles, they grew more and extended their projections (called neurites) further and faster, depending on how much the muscles contracted.

Additionally, the mechanical stimulation that the researchers applied caused the neurons to grow similarly to when they were exposed to muscle-released molecules, even without direct contact with muscle cells.

The mechanical effects of exercise on motor neurons are generally not well studied, but these results show that these forces significantly influence neuron growth and movement.

However, RNA analysis showed that biochemical and mechanical stimulation affected the neurons in different ways, with biochemical signals having a stronger effect on nerve growth and connections.

Overall, the results of the study demonstrate how muscle contraction helps motor neurons grow and mature, a process that is generally hard to study in living systems.

By separating the mechanical and biochemical effects of muscle activity, the researchers gained a deeper understanding of how muscles influence nerves.

Practical Implications

So, why does this all matter?

This study is an initial step in understanding how muscle contractions influence motor neuron growth and development through both chemical and mechanical signals.

By building on this discovery, researchers can better understand how exercise shapes the connections between muscles and nerves in both healthy and diseased conditions.

Over time, the researchers aim to apply their methods in the lab to develop therapies that use chemical stimulation and mechanical treatments to maintain and improve mobility.

The findings suggest that muscle-stimulating therapies can potentially be used to help heal nerve damage.

This could be significant for those who suffer from immobility due to a muscle-nerve disconnect.

The same approach used in this study could also be used in the future to analyze how muscles communicate with other types of cells during exercise, improving our knowledge of how different tissues interact in the body.

Beyond motor neurons, the researchers hope that their magnetic materials, which are simple to make, can help other researchers study how muscles interact mechanically with various types of cells. 

Take Home Message

There you have it, when they say exercise invigorates your body, they mean it literally. This study showed that by exercising, you can help your brain cells grow and function properly. That’s one more reason to hit the gym, right?