The Effect of Swimming on the Human Cardiovascular System

Swimming is excellent cardiovascular exercise. Through swimming, physically challenged, elderly, pregnant and overweight athletes who cannot participate in other sports can improve their cardiovascular fitness.
    • Swimming produces many cardiovascular adaptations.

    Heart

    • Swimming increases the size of the heart's chambers, the thickness of its walls and the space available for it in the chest. All of these factors increase the amount of blood your heart pumps per beat (stroke volume).

    Blood

    • Within one week, swimming increases blood volume up to 15 percent. After six weeks, swimming increases the amount of hemoglobin (oxygen-carrying red blood cells) in the blood.

    Capillary Density

    • Over time, a swimmer enhances oxygen delivery by developing more capillaries in his swimming muscles.

    Heart Rate Adaptations

    • Swimming lowers the resting heart rate and trains the heart to recover a low heart rate quickly after hard efforts. Although it doesn't increase maximum heart rate, increased stroke volume developed through swimming improves maximum cardiac output.

    Blood Pressure

    • Because a swimmer's heart doesn't have to overcome gravity to pump blood to working muscles, swimming doesn't increase exercising blood pressure.

    Cellular Adaptations

    • Swimming increases the number of mitochondria ("the powerhouse of the cell"), allowing the swimmer's muscles to use more oxygen from the blood. The increased mitochondrial volume means a swimmer produces more power at a given effort.