Traditionally, improvements in endurance have been attributed to structural and functional changes within muscle fibers resulting from training. However, new research suggests that brain activity plays a crucial role in building stamina, and without it, the benefits of exercise are diminished. Understanding the brain’s role in exercise response could open new avenues for improving fitness, particularly for those with limited mobility.
A study conducted by researchers at The Jackson Laboratory reveals that enhancing endurance isn’t solely dependent on changes in muscle tissue; it also involves the activation of specific neuron populations in the brain. The findings were published in the journal Neuron.
In experiments with mice, blocking the activity of certain neurons prevented gains in endurance, regardless of the intensity of treadmill training. Conversely, artificially activating these neurons after exercise led to further improvements in stamina.
Researchers monitored brain activity during and after running, identifying a group of neurons in the hypothalamus that express a protein called steroidogenic factor 1 (SF1). These neurons remained active for approximately one hour after exercise concluded.
As the mice underwent several weeks of training, an increasing number of SF1 neurons were activated after each session, and the connections between them grew more numerous and stronger. Animals that exercised had roughly twice as many connections between these neurons compared to their sedentary counterparts.
When SF1 neurons were deactivated for 15 minutes following each training session, the mice showed no further improvement in endurance and performed worse on running tests.
Stimulating the SF1 neurons for one hour after each treadmill session, however, resulted in additional gains in endurance and allowed the mice to achieve higher peak speeds than typically attained through training alone.
The study authors suggest that this neuronal circuit could be harnessed to amplify the effects of moderate exercise, particularly for older adults or individuals with mobility limitations who may not be able to engage in intense physical activity but could still benefit from the protective effects of movement on the brain and body.
Â
Â
