The primary function of the heart is to pump oxygenated blood throughout the human body as part of the circulatory system. When a person exercises, the heart rate, otherwise known as the pulse, will increase rapidly with the output of energy. Both the breathing rate and the pulse rate will substantially increase with exercise.
How the Heart Functions
The inside of the heart contains two separate pathways for circulation. These are the systemic circuit and the pulmonary circuit. The systemic circuit uses the left ventricle of the heart to pump oxygenated blood through the aorta to the arteries and capillaries, thus supplying the human body with oxygen. The pulmonary circuit sends deoxygenated blood through the right ventricle and pulmonary artery to the lungs, which in turn will send oxygenated blood to the left atrium of the heart. The ventricles comprise the lower chambers of the heart, and the atria comprise the top chambers.
A Pulse Increase
The arteries expand as the ventricles pump this blood out of the heart, and this is known as a pulse. Fundamentally, exercise will increase the need for additional food, known as energy, and oxygen in the body. The breathing will increase to rid the body of carbon dioxide and to provide more oxygen, and the pulse will increase to provide the extra food and oxygen needed.
Recovery Time and the Oxygen Debt
The body of a physically fit person produces less lactic acid during glucose production. A body that produces less lactic acid fosters a more efficient heart and lungs, thereby having less muscle fatigue during exercise as the heart pumps oxygen to the body more rapidly. Recovery time is also known as the amount of time it takes the human body to repay an "oxygen debt." A person in poor physical shape will require much more recovery time to keep exercising.
Importance of a Cool Down
A cooling down period is important after exercise to help reduce the amount of stress put on the heart. Instead of stopping strenuous exercise such as running abruptly, slow the body down to a light jog or walk. Three to seven minutes is an adequate cooling down period so that the heart and muscles can relax gradually.