Students exercise during gym class at the International Leadership of Texas Keller-Saginaw High School on Monday, October 2, 2017 in Saginaw. (David Woo/The Dallas Morning News) .
David Woo/Staff Photographer
Pills arranged around an anatomical copy of a human brain on a blue background. Memory and brain health supporting supplements concept.
norcal-marketing
Consistency is key to building an exercise routine. But with each workout, something else is taking shape: the brain is adapting, rewiring itself in ways that help the body go farther and last longer, according to new research.
In a recent study published in the journal Neuron, scientists at UT Southwestern Medical Center, the University of Pennsylvania, Vanderbilt University and other institutions found specific brain cells in mice become more active after a bout of exercise. Over time, those cells grow more responsive and better connected. The memory formed in mouse brains appears to help their bodies build endurance and use energy more efficiently. In contrast, when the researchers blocked those brain cells after exercise, the mice failed to improve their endurance.
Article continues below this ad
“Most people think of the body adapting to exercise through the muscles, heart, lungs, and other tissues. But our study shows that the brain itself can program endurance capacity,” Kevin Williams, an associate professor of internal medicine at UT Southwestern who co-led the new study, said in a news release.
Harder, better, faster, stronger
Several studies have shown the brain changes with exercise, helping reduce neuroinflammation, promote the growth of new neurons and strengthen connections between them. That is why regular aerobic exercise is often recommended to support brain health, including to alleviate mental health conditions such as depression and lower the risk of neurodegenerative diseases such as Alzheimer’s.
Kevin Williams is an associate professor of internal medicine at UT Southwestern Medical Center who co-led the new study.
UT Southwestern Medical Center
But while scientists have long known about these benefits, they were often considered a side effect and not a driving force behind the physiological adaptations that come with a repeated sweat session.
Article continues below this ad
Make Dallas News a preferred source so your search results prioritize writing by actual people, not AI.
Add Preferred Source
To understand what’s driving those changes, Williams and his colleagues focused on the hypothalamus, a region of the brain that helps regulate energy use. Cells in this area respond to signals like hormones and blood sugar levels to control how much energy the body burns. A specific group of these cells — known as steroidogenic factor-1 (or SF-1) neurons — has been linked in past research to endurance. When their activity is reduced, the usual gains from exercise are blunted, suggesting they play a key role in how the body adapts to physical activity. But until now, scientists did not fully understand how these neurons contribute to the body’s response to repeated exercise.
Williams and his colleagues made six-week-old mice run on a tiny treadmill five days a week, with a single weekly long run that increased in speed. This training significantly raised their endurance, which peaked about three weeks into the program.
After eight days of exercise, more SF-1 neurons in the hypothalamus became active and developed tiny structures — called synaptic spines — that allow brain cells to communicate. After weeks of regular exercise, these neurons became more active and easier to trigger, allowing the mice to run farther over time; compared with those of sedentary mice, the neurons fired more often and were less likely to remain inactive.
Article continues below this ad
UT Southwestern researchers and colleagues studied brain cells in the hypothalamus called steroidogenic factor-1 neurons, which they found to be crucial to many of the metabolic benefits of exercise.
UT Southwestern Medical Center
Using a method that uses light to control brain cells, researchers switched SF-1 neurons on and off after exercise. Turning them off prevented improvements in endurance, while boosting their activity enhanced performance. Even when the mice continued to train, those with silenced SF-1 neurons made fewer gains, running shorter distances and at slower speeds.
By signing up, you agree to our Terms Of Use and acknowledge that your information will be used as described in our Privacy Policy.
“One of the more interesting implications of this study is that we traditionally think of increases in athletic performance occurring by building the musculoskeletal, cardiovascular, and respiratory systems as an adaptive response to training,” Nicholas Betley, an associate professor of biology at the University of Pennsylvania who co-led the study, said in the news release. “Here, we identify the brain as a critical intermediate in this process.”
Article continues below this ad
Because the study focused on mice, it remains unclear how its findings might apply to humans. In the paper, the researchers said it’s not fully understood how the SF-1 neurons are switched on during exercise or how they interact with other brain circuits. Even the timing of their activity — whether they fire during a workout or afterward — appears to shift with training and is not well understood.
Future research will need to map the broader neural networks involved and trace how signals from the body reach these brain cells. Scientists will also need to determine whether targeting these pathways could safely enhance endurance or mimic benefits of exercise — perhaps one day bringing us closer to a pill that delivers similar effects.