Want New Brain Cells? Exercise Makes Them Happen

A new study in mice shows how physical activity triggers a chain reaction that helps the brain grow new cells.

We all know exercise is good for the body. But did you know it might also help your brain grow new neurons?

A new study suggests that when you exercise, your muscles send signals to the brain that cause a special type of brain cell called an astrocyte to contract, or squeeze. And that contraction may trigger the growth of new brain cells.

What Are Astrocytes?

Astrocytes are star-shaped cells in the brain and spinal cord. They are some of the first cells to notice what is happening in the body, and they help neurons grow and repair themselves.

What Happens When You Exercise?

The researchers studied mice to understand this process better.

First, they found that when mice ran on a wheel, their astrocytes contracted almost immediately.

Next, they took mouse muscle cells and collected the substances they released when they contracted. They applied these substances to astrocytes in a dish — and the astrocytes contracted too.

Finally, they collected the substances released by the contracting astrocytes and added them to mouse brain cells. The result? More immature neurons were produced. The more the astrocytes contracted, the more new neurons appeared.

A New Discovery

“The astrocytes are contracting in response to exercise, and the contraction is like a new force in the brain that we didn’t realise before,” said researcher Justin Rhodes.

Scientists are still figuring out exactly why this happens. One idea is that the contraction makes it easier for the cell membrane to let things pass through. Another is that it helps release important chemicals that help neurons grow.

What This Means for Humans

While this study was done in mice, experts believe a similar process likely happens in humans too. “This is a fascinating and novel finding,” said Flaminia Ronca from University College London.

Understanding this process better could one day lead to new treatments for brain health and cognitive decline.

The Bottom Line

The study shows that exercise sets off a surprising chain reaction: muscles contract → astrocytes contract → new neurons grow.

So the next time you go for a run or a walk, remember — your brain is getting a workout too.