Exercise is widely known for strengthening muscles and improving physical fitness. However, scientists are now discovering that regular workouts may also create important changes in the brain that help improve endurance and overall performance.

A new study published in the Cell Press journal Neuron suggests that the long-term improvements people experience from repeated exercise—such as running farther or maintaining higher speeds—may partly be driven by changes in brain activity that support the body’s heart and muscles.

“Many people say they feel mentally sharper or clearer after exercising,” explained J. Nicholas Betley, a neuroscientist at the University of Pennsylvania and the study’s corresponding author. “We wanted to understand what actually happens inside the brain after exercise and how those changes contribute to the benefits of physical activity.”

The Brain’s Role in Building Endurance

To explore this question, Betley and his research team conducted experiments using mice running on treadmills.

After the animals completed their workouts, scientists observed increased activity in several areas of the brain. The most significant changes occurred in neurons located in the ventromedial hypothalamus (VMH)—a region responsible for regulating how the body manages energy, including processes that influence body weight and blood sugar levels.

Using real-time neural tracking technology, the researchers identified a specific group of neurons called steroidogenic factor-1 (SF1) neurons. These neurons became highly active during running.

Interestingly, their activity did not stop once the exercise ended. Instead, the SF1 neurons remained active for at least an hour after the mice stopped running.

Training Increased Both Brain Activity and Performance

The mice followed a daily training routine for two weeks. Over time, their endurance improved significantly.

By the end of the training period, the animals were able to run longer distances and maintain higher speeds before becoming fatigued.

When scientists examined the brain activity of these mice, they discovered that more SF1 neurons were activated after training, and the neurons themselves showed higher overall activity levels compared with the beginning of the study.

To determine whether these neurons were essential for endurance development, researchers conducted an additional experiment.

When SF1 neurons were blocked from sending signals to other parts of the brain, the mice quickly became exhausted during workouts and failed to improve their endurance throughout the two-week training program.

Why Brain Activity After Exercise Matters

One surprising finding emerged when researchers switched off the SF1 neurons only after the exercise session ended.

Even though the neurons functioned normally during the workouts themselves, shutting them down afterward eliminated the endurance improvements entirely.

This suggests that the brain activity occurring after exercise may be just as important as what happens during the workout.

Exercise May Strengthen the Brain

According to Betley, the results challenge the traditional view that exercise mainly benefits muscles.

“When we lift weights or run, we usually think we’re just building muscle,” he said. “But our findings suggest that exercise may also be strengthening the brain.”

Although scientists are still studying the exact biological processes involved, Betley believes the continued activity of SF1 neurons after exercise may help the body recover more efficiently by improving how stored glucose is used.

Better energy management could allow the heart, lungs, and muscles to adapt more effectively to repeated physical training.

Potential Benefits for Health and Recovery

The research could eventually lead to new ways to help people stay active and healthy.

The team believes these discoveries may benefit older adults, stroke survivors, or individuals with mobility challenges, helping them improve endurance and maintain physical activity.

The findings could also help athletes or patients recovering from injuries train more effectively.

“This research opens the door to understanding how we might maximize the benefits of exercise,” Betley said. “If we can help people see results sooner, it could motivate more individuals to stay active.”