Exercise has positive effects on the brain

The article briefly describes the positive effects of exercise. Studies show that regular exercise changes the brain. In people who walked regularly in an experiment, the hippocampus grew larger. This is a brain structure that is essential for memory. Walking also had a positive effect on memory.

This is just one study among many. In 2025, scientists from Australia and the US published a large review article. They examined all existing literature and combined the data from these studies into a new analysis (a meta-analysis) covering roughly 260,000 participants.

Their conclusion: exercise is good for memory and boosts mental capacity, even at low intensity. It is also good for the brain’s executive functions. Think of the speed of action, but also the ability to carry out movements well and precisely (Singh, Br J Sports Med, 2025). Researchers are currently studying the underlying mechanisms of these positive effects in depth.

The muscle-brain axis

More and more research suggests that when we use our muscles, they release certain substances that can have a positive effect on the brain. This biological communication system between the muscles and the brain is also known as the muscle-brain axis. These substances released by muscles are called myokines (from the Greek “myo,” meaning muscle). More than 600 different myokines are now known, and a few of them are known to directly or indirectly influence the hippocampus.

A good example of such a myokine is the molecule cathepsin B. Several successive studies showed how cathepsin B plays a role in the muscle-brain axis. A first experiment showed that cathepsin B is released by the muscles during exertion. Another experiment then showed that when this substance is given to nerve cells from the hippocampus of mice, these cells produce BDNF (brain-derived neurotrophic factor). BDNF is a substance that ensures new nerve cells are created and that nerve cells in the brain can survive.

BDNF also helps nerve cells settle into a neural network by forming connections with other nerve cells and strengthening those connections. It also plays an important role in memory. A final experiment with mice showed that when cathepsin B was switched off, the mice were less able to remember their spatial orientation. In short, the molecule was important for transferring spatial information from short-term to long-term memory.

These positive effects on memory were also seen in humans. In one study, participants trained on a treadmill for four months, which increased the concentration of cathepsin B in their blood. It turned out that the more the cathepsin B concentration increased, the better participants scored on a memory test taken just before and after the training program.

Irisin and lactate: two other myokines

Irisin and lactate are two other myokines that are released by the muscles during exertion and influence the brain via BDNF. Irisin has been studied extensively in recent years in Alzheimer’s research, because people with Alzheimer’s were found to have reduced levels in the hippocampus.

The effects of exercise in pill form?

The article is rather skeptical about whether we can get the effects of exercise from a pill. In the past, treatments with a single molecule often had side effects (EOS Psyche en Brein, no. 3, 2026, “How exercise also makes your brain fitter”).

And why choose a single pill when you can also enjoy being active? Indoors with Bike Labyrinth, for example, or outdoors if you still can. That way you put many of your myokines to work.