Swimming may be a more effective way to strengthen the heart and improve cardiac muscle function than running, according to a new study by Brazilian scientists. The research, conducted by specialists at the Federal University of São Paulo (Unifesp) and released Monday by the São Paulo State Research Support Foundation (Fapesp), suggests that water-based exercise promotes healthier heart growth and a greater capacity for myocardial contraction.
Researchers found that while both swimming and running improve respiratory capacity, swimming goes further by combining functional and molecular adaptations that build the heart stronger and more efficient. “We discovered that, although both activities improve respiratory capacity, swimming goes beyond, combining functional and molecular adaptations that make the heart stronger and efficient,” said Andrey Jorge Serra, the study’s coordinator and a researcher at Unifesp.
The study, published in the journal Scientific Reports, identified that swimming’s superiority is linked to greater modulation of microRNAs. These molecules regulate gene expression and control key processes in the heart, including cardiac cell growth, new blood vessel formation, protection against cell death, and response to oxidative stress. Understanding these mechanisms could have implications for cardiac rehabilitation and recovery.
For the study, researchers subjected rats to an eight-week training protocol, with daily 60-minute sessions five times per week. The subjects were divided into three groups: a sedentary control group, a running training group, and a swimming training group, according to a statement released by Fapesp.
Results showed that both running and swimming improved physical fitness similarly, with a greater than five percent increase in maximum oxygen consumption – a key indicator of cardiorespiratory capacity. However, only swimming generated significant structural changes in the heart, including increased cardiac mass and left ventricular size.
“Our results show that swimming may have a special impact on myocardial recovery and cardiac rehabilitation, in addition to providing relevant evidence for scientific research, since the effects of different exercise modalities are not equivalent,” Serra explained. The findings suggest that different types of exercise may have varying benefits for heart health, potentially informing personalized exercise recommendations.
The study also analyzed gene and protein expression pathways involved in physiological cardiac hypertrophy, furthering the understanding of the molecular mechanisms associated with the benefits of aerobic exercise.
