Compared to running, what is the effect of swimming on heart rate, even at the same exercise intensity?

Swimming generally results in a lower heart rate compared to running at the same exercise intensity, primarily due to the unique physiological demands and adaptations associated with the water environment. When swimming, the body is partially immersed in water, which provides buoyancy and reduces the overall impact on the cardiovascular system. This leads to enhanced venous return due to hydrostatic pressure, allowing for improved stroke volume and cardiac efficiency.

Additionally, swimming involves a horizontal position, which helps to decrease the gravitational load on the heart compared to running, where the body is upright and working against gravity. Consequently, the heart may not need to pump as quickly to meet the body's oxygen demands during swimming as it does during running.

This lower heart rate response during swimming demonstrates the benefits of engaging in different forms of exercise, each of which can present unique cardiovascular responses based on the mechanics and characteristics of the activity. Therefore, at the same perceived exertion level, swimmers tend to maintain a lower heart rate than runners.