Regular exercise may benefit your heart in ways that scientists are only beginning to understand. In addition to improving cardiovascular health, new research suggests that moderate aerobic exercise reshapes the nerves that regulate the heart. The findings could ultimately help doctors develop more precise treatments for common heart conditions.
Researchers at the University of Bristol, UK, have discovered for the first time that regular aerobic training causes different changes in the nerves that control the heart on the left and right sides of the body. This study autonomic neuroscienceone day revealed significant laterality differences that may improve treatment strategies for arrhythmia, chest pain, angina, and stress-induced “broken heart” syndrome.
Dr Augusto Coppi, lead study author and Senior Lecturer in Veterinary Anatomy at the University of Bristol, said: “Our findings show that there is a previously hidden left-right pattern in the body’s ‘autopilot’ system that helps the heart work.”
“We showed that these nerve clusters act like dimmer switches for the heart, and that regular, moderate exercise switches them on in a unilaterally specific way. This may help explain why some treatments work better on one side, and could help doctors deliver treatments more accurately and effectively in the future.”
Exercise changes the nerves that control the heart
The project was carried out in collaboration with University College London (UCL) in the UK, the University of São Paulo (USP) and the Federal University of São Paulo (UNIFESP) in Brazil. The research team used an advanced three-dimensional imaging technique known as stereology to examine how exercise changes nerve clusters that help regulate heart function.
After 10 weeks of training, the exercised rats had about four times as many neurons in the cardiovascular nerve complex on the right side of their bodies compared to the left side, compared to untrained rats. At the same time, the neurons on the left almost doubled in size, and the neurons on the right became slightly smaller. These findings suggest that exercise restructures the heart’s neural networks differently on each side.
Potential benefits of cardiac therapy
Dr. Coppi explained: “Irregular heart rhythms known as arrhythmias, stress-induced ‘broken heart’ syndrome, and certain types of chest pain are often treated by suppressing the activity of overactive stellate ganglia (a pair of small nerve hubs in the lower neck/upper chest that send ‘go faster’ signals to the heart).
“By mapping how exercise changes the ganglia on each side, this study provides clues that could one day fine-tune treatments such as nerve blocks or denervation to the side where they are most likely to be effective. This finding is in early stages in rats, so clinical studies will need to follow.”
Although the study is still in its early stages and was conducted in rats, the results raise the possibility that future treatments can be tailored to target one side of these neural clusters more effectively than the other. This approach could improve the treatment of arrhythmia, stress-induced “broken heart” syndrome, and difficult-to-treat angina pectoris.
Next steps in research
The researchers now plan to investigate how these structural changes affect the heart’s performance both during exercise and at rest. They also plan to use non-invasive markers to determine whether the same left-right pattern appears in other animal models or in humans.
Dr. Coppi added: “Understanding these left-right differences may help to personalize treatments for heart rhythm disorders and angina pectoris. Our next step is to test how these structural changes map to function and whether similar patterns emerge in larger animals and humans.”
