A new study has shown the brain actively directs the body’s endurance adaptations, revealing that a specific cluster of neurons in the ventromedial hypothalamus governs stamina gains after regular exercise in mice. The scientists found that activating SF1 neurons immediately after a workout is necessary for long‑term increases in endurance, a discovery published in Neuron in May 2026. The work was led by Morgan Kindel of the University of Pennsylvania and Ryan J. Post of Providence College, with a team of collaborators.
Historically, exercise physiology has focused on the body’s periphery — muscles, the cardiovascular system and immune function — with the brain thought to mirror these changes rather than drive them. The ventromedial hypothalamus acts to regulate energy expenditure, feeding and blood sugar, and within this region a subset of neurons expresses a protein known as steroidogenic factor‑1, or SF1. Researchers hypothised these SF1 neurons might play an active role in how the body copes with the metabolic stress of training.
In a series of mouse studies, the team first exposed a small group to a single treadmill session and examined brain tissue for expression of the Bdnf gene, which rises when neurons fire. They found more SF1 neurons expressing Bdnf and higher transcript levels per cell, indicating the exercise session successfully engaged the neural population.
To test what happens if this neural activity is blocked, the researchers delivered a toxin designed to stop SF1 neurons from releasing signals. When subjected to a progressively challenging treadmill test, the mice with silenced SF1 neurons reached exhaustion sooner than control animals. Indirect calorimetry revealed these mice burned through carbohydrate stores prematurely rather than switching to fat use.
Next came a three‑week treadmill training protocol to assess endurance gains. Control mice improved in running time and distance, whereas mice with silenced SF1 neurons failed to build endurance. Muscle analyses showed the usual training‑related metabolic gene changes were absent in the silenced group, suggesting brain silencing hindered muscular adaptation.
To observe neuronal activity in real time, the team employed miniature head‑mounted microscopes to monitor calcium levels in active SF1 neurons. Over a week of daily training, a subset of these neurons repeatedly lit up in the minutes after running, with both their numbers and firing strength increasing with continued training.
Further tissue analysis after three weeks revealed that trained SF1 neurons were more electrically excitable, firing spontaneous action potentials more readily. High‑resolution imaging showed a doubling in dendritic spine density, a structural sign the cells had formed more synaptic connections in response to exercise.
To establish causality, researchers used optogenetics to inhibit SF1 neurons for 15 minutes immediately after each daily session. This brief post‑exercise suppression reduced the endurance gains the mice would otherwise have achieved.
Conversely, another experiment delivered targeted stimulation to SF1 neurons for an hour after exercise, which boosted endurance beyond the animals’ normal physiological plateau. The stimulation increased blood sugar and overall energy expenditure, a pattern the researchers say may help trigger the metabolic signals that prime muscles for future stress.
The authors caution that the work is conducted in mice and metabolic processes do not map perfectly onto human physiology, noting that human endurance adaptations occur over longer time scales with more varied training. They say the findings do not yet explain precisely how the brain interprets the end of exercise, and call for future studies to identify the physical pathways that relay fatigue signals from muscles to the ventromedial hypothalamus, and to determine whether other forms of exercise recruit the same neural circuitry. If validated in humans, the work could inform strategies for people unable to engage in rigorous activity.
The study, Exercise-induced activation of ventromedial hypothalamic steroidogenic factor‑1 neurons mediates improvements in endurance, was published in May 2026 and authored by Morgan Kindel, Ryan J. Post, Kyle Grose, Louise Lantier, Eunsang Hwang, Jamie R.E. Carty, Lenka Dohnalova´, Lauren Lepeak, Hallie C. Kern, Rachael Villari, Nitsan Goldstein, Emily Lo, Albert Yeung, Lukas Richie, Bridget Skelly, Jenna Golub, Manmeet Rai, Teppei Fujikawa, Julio E. Ayala, Joel K. Elmquist, Christoph A. Thaiss, David H. Wasserman, Kevin W. Williams, Erik B. Bloss, and J. Nicholas Betley.
