Physical activity changes the structure of the heart's nerve nodes.
A new study has shown that regular aerobic exercise affects not only the heart but also the nerve nodes that regulate its function. These nodes—the stellate ganglia—are located in the neck area and are involved in controlling heart rate and the heart's response to stress. The work is published in Autonomic Neuroscience (AN).
In the experiment, rats underwent moderate treadmill training for 10 weeks, after which the researchers examined changes in the left and right ganglia. It was found that training caused different changes on the right and left sides. Physically active animals had about four times more nerve cells in the right ganglion than in the left, while untrained animals showed no such difference. At the same time, the size of the cells changed in the opposite way: in the right ganglion, they became smaller, while in the left, they significantly increased.
The researchers also found that the overall volume of these nerve nodes decreased after training, especially on the right side. This indicates that physical activity leads not simply to "strengthening" or "weakening" of the nervous system but to a more complex restructuring of its structure.
The authors believe that such asymmetric changes may play an important role in how the body adapts to regular stress and how the nervous system supports heart function. In the future, this knowledge could help better understand the mechanisms of cardiac regulation and develop more precise approaches to treating arrhythmias; however, the results have so far been obtained only in animals.
