New research suggests it also physically reshapes the nerves that control the heart, revealing an unexpected difference between the left and right sides of the body. Scientists at the University of Bristol (UK) discovered that moderate aerobic exercise changes the structure of nerve cells involved in regulating heart activity. Even more surprisingly, the changes were dramatically different on the two sides of the body.
The findings, published in Autonomic Neuroscience, could eventually help doctors develop more precise treatments for irregular heartbeats, chest pain, angina, and stress-induced 'broken-heart' syndrome. The discovery was made in rats, so further research is needed to determine whether the same changes occur in humans. Nevertheless, it offers a new perspective on how physical activity influences the nervous system that keeps the heart functioning.
Exercise Changes the Heart's Hidden Control System The heart is regulated partly by the autonomic nervous system, a network of nerves that automatically manages essential functions such as heartbeat, breathing, and digestion. One branch of this system helps the heart beat faster when the body needs more oxygen, such as during exercise or stressful situations. Small clusters of nerve cells called stellate ganglia play an important role in this process.
Located on both sides of the lower neck and upper chest, these nerve hubs send signals that influence heart rate and other aspects of heart function. The new research suggests that regular exercise changes these nerve clusters in ways scientists had not previously recognized. Augusto Coppi, Senior Lecturer in Veterinary Anatomy at the University of Bristol, said: "The discovery points to a previously hidden left-right pattern in the body's 'autopilot' system that helps run the heart.
"These nerve clusters act like the heart's dimmer switch and we've shown that regular, moderate exercise remodels that switch in a side-specific way. This could help explain why some treatments work better on one side than the other and, in future, help doctors target therapies more precisely and effectively." Just 10 Weeks of Exercise Produced Striking Nerve Changes To investigate how exercise affects these nerve clusters, the researchers examined rats that underwent 10 weeks of moderate aerobic training. Aerobic exercise is physical activity that increases heart rate and breathing, such as brisk walking, swimming, or cycling.
The study involved researchers from University College London (UCL) in the UK, the University of São Paulo (USP), and the Federal University of São Paulo (UNIFESP) in Brazil. The team used advanced three-dimensional analysis techniques known as stereology to examine the nerve cells. This approach allows scientists to estimate the number, size, and distribution of cells within tissues.
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