Exercise may reshape heart-control nerves, rat study finds
University of Bristol researchers say aerobic training changed left and right heart-control nerve hubs differently in rats.
By Lucas Ferreira · Science & Environment Writer
3 min read
Moderate aerobic exercise altered the nerve hubs that help control the heart in a rat study led by the University of Bristol. The finding could help researchers refine side-specific treatments for arrhythmias, angina and stress-induced “broken-heart” syndrome, though the work remains early and has not yet been confirmed in humans.
The study, published in Autonomic Neuroscience, examined stellate ganglia, paired nerve clusters in the lower neck and upper chest that send signals influencing heart activity. According to the University of Bristol, the work suggests exercise changes these nerve hubs in different ways on the left and right sides of the body.
Researchers from Bristol worked with University College London, the University of São Paulo and the Federal University of São Paulo. The team used three-dimensional imaging methods known as stereology to measure structural changes in the nerve clusters after aerobic training.
After 10 weeks, the exercising rats showed a pronounced side-to-side difference in the neurons linked to cardiovascular control, according to the university. Compared with untrained animals, trained rats had about four times as many neurons on the right side as on the left, while neurons on the left nearly doubled in size and those on the right became slightly smaller.
Dr. Augusto Coppi, senior lecturer in veterinary anatomy at the University of Bristol and the study’s lead author, said the results reveal a left-right pattern in the autonomic nervous system, which helps regulate involuntary heart functions. Coppi said the findings may help explain why treatments aimed at these nerve hubs can perform differently depending on which side is targeted.
Doctors already use approaches that reduce activity in overactive stellate ganglia for some heart-related conditions, according to Coppi. Those conditions include irregular heart rhythms, some forms of chest pain and stress-induced “broken-heart” syndrome.
The research points to a possible future in which nerve blocks or denervation procedures could be aimed more precisely at the side most likely to help a patient, the University of Bristol said. The researchers cautioned that the work was done in rats, so clinical studies would be needed before the findings could influence care.
The next step is to test how the structural differences affect heart function during exercise and rest, according to the research team. Coppi said researchers also want to see whether similar left-right patterns appear in larger animals and in humans, using non-invasive markers.
The journal article is titled “Asymmetric neuroplasticity in stellate ganglia: Unveiling side-specific adaptations to aerobic exercise.” Its authors include Fernando Vagner Lobo Ladd, Aliny Antunes Barbosa, Renato Albuquerque de Oliveira Cavalcanti, Larissa Freitas, Reinaldo Barreto Oriá, Ricardo Mario Arida, Mariana Pereira de Melo, Andrzej Loesch and A. Augusto Coppi.
This story draws on original reporting from ScienceDaily.