Exercise doesn't just strengthen your heart. It rewires it
Regular exercise does more than strengthen the heart. New research reveals that it actually reshapes the nerves controlling how the heart functions, and the changes are surprisingly different on the left and right sides of the body.
Key points
- Moderate aerobic exercise in rats changed the structure of nerve clusters that regulate the heart.
- The right-side nerve cluster had about four times as many neurons as the left after training.
- The findings could eventually help target treatments for arrhythmias and angina more precisely.
New research from the University of Bristol in the UK suggests that moderate aerobic exercise does more than strengthen the heart: it also physically reshapes the nerves that control it. The study, published in Autonomic Neuroscience, found that exercise produced dramatically different changes on the left and right sides of the body.
The discovery was made in rats that underwent 10 weeks of moderate aerobic training. Scientists say further research is needed to determine whether the same changes occur in humans.
What the study found
The researchers examined small clusters of nerve cells called stellate ganglia, which sit on both sides of the lower neck and upper chest and help regulate heart rate. Using advanced 3D analysis techniques known as stereology, they found that in trained rats the right-side cluster contained roughly four times as many neurons as the left-side cluster, a striking difference from untrained rats.
The neurons also changed size in opposite directions: cells on the left nearly doubled in size, while those on the right became slightly smaller. The team included researchers from University College London and two universities in Brazil.
The discovery points to a previously hidden left-right pattern in the body's 'autopilot' system that helps run the heart.
— Dr. Augusto Coppi
Potential for better treatments
The findings could eventually help doctors refine procedures such as stellate ganglion nerve blocks or denervation, which reduce excessive nerve signals to the heart in conditions like arrhythmias, angina and stress-induced 'broken-heart' syndrome.
Study lead author Dr. Augusto Coppi said the work "offers clues that could one day fine-tune procedures like nerve blocks or denervation to the side most likely to help." He noted the results are early-stage and in rats, so clinical studies would be needed. The team plans to test how the structural changes affect heart function and to look for similar patterns in larger animals and humans.
