In order to maintain the vital signs of the human body, the heart must have a fixed cardiac output to ensure the blood supply and nourishment of the body, therefore the cardiac output is definite as per the body's needs. When there is severe mitral valve regurgitation, it causes a decrease in the stroke volume. As a compensation, while the stroke volume decreases, in order to ensure the body's blood supply and nourishment, the heart accelerates its beating to maintain the supply of output. Therefore, patients with mitral valve regurgitation often experience symptoms of tightness in the chest, difficulty breathing, and palpitations after exercising. This means that our heart rate after exercise will be faster than in people without mitral valve regurgitation, thus mitral valve regurgitation affects the heart rate.