Swimming vs. Running: Study Finds Key Differences in Heart Health
Swimming may do more for your heart than running, according to new research. But there's an important catch: the findings come from animal studies, not humans.
In a recent study published in Scientific Reports, researchers found that mice that swam regularly showed greater improvements in heart structure and function compared to those that ran.
The study was led by scientists at the Federal University of São Paulo and supported by the São Paulo Research Foundation.
"Swimming and running are two excellent ways to improve cardiorespiratory health and protect the heart muscle, but we wanted to know if one could be even more beneficial than the other. We found that, although both increase respiratory capacity, swimming goes a step further by combining functional and molecular adaptations that make the heart stronger and more efficient," says Andrey Jorge Serra in a news release. She's a professor at UNIFESP and coordinator of the study supported by FAPESP.
What the Study Found
The mice underwent an eight-week training program consisting of daily hour-long sessions, five days per week. Swimming showed a significant increase in cardiac and left ventricular mass, compared to the runners.
The mice were evaluated before and after the training periods to see if their fitness and heart function changed in any way.
Benefits of Swimming
Swimming is great because it's easy on your joints, which is beneficial for people with arthritis or have obesity, which reduces mobility, according to the Cleveland Clinic.
Swimming can:
- Improve cholesterol levels
- Lower blood pressure
- Strengthens your lung capacity
Swim or Run?
How you exercise should mainly depend on what you enjoy and are likely to stick with. Whatever you prefer, the American College of Sports Medicine recommends you do moderate-intensity exercises about 150 minutes per week, which is only 20 minutes each day. Listen to your body. If it hurts, stop and rest.
"People's choice of sport depends largely on personal preference, aptitude, and enjoyment. But our results show that swimming may have a special impact in situations involving myocardial recovery, cardiac rehabilitation, and above all, scientific research. This is also relevant because studies on aerobic exercise often use running and swimming interchangeably, and we now know that the effects aren't the same," Serra said.
Swimming and running both strengthen the heart. But early research suggests swimming could offer additional benefits, at least in animal models.
Until more human data is available, experts say the key is simple: stay active, choose exercises you enjoy, and listen to your body.
This story was originally published by Men's Journal on Apr 29, 2026, where it first appeared in the News section. Add Men's Journal as a Preferred Source by clicking here.
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This story was originally published April 29, 2026 at 2:41 PM.