Aerobic exercise decreases your risk of heart disease -- the No. 1 cause of death in all 50 states as of 2009. Your cardiovascular system regulates blood flow and comprises your heart, arteries, veins and capillaries. Aerobic activities such as walking, swimming and cycling target your heart and improve sports performance as well as health. Understanding cardiovascular adaptations enables informed fitness decisions.
Heart Rate
Heart rate equals the number of times your heart beats per minute. Over time, aerobic exercise can reduce your heart rate at rest and during exercise. While a typical resting heart rate falls between 60 and 100 beats per minute, elite athletes can possess resting heart rates below 40 beats per minute.
Stroke Volume
Stroke volume represents the amount of blood pumped through one of four heart chambers during a single heartbeat. Aerobic exercise strengthens your cardiac muscle, enabling increased stroke volume, or SV. An enhanced SV permits your heart to pump more blood per beat.
Cardiac Output
Cardiac output, or CO, defines the amount of blood pumped through all four heart chambers per minute. CO increases with SV and improves blood circulation. For example, a heart with a lower CO must beat faster during exercise than a heart with a greater CO.
Blood Pressure
Blood pressure measures the force exerted by blood on the wall of a blood vessel. While systolic blood pressure measures pressure during a heart contraction, diastolic blood pressure measures the lowest pressure between contractions. Although your blood pressure can rise during exercise, physical activity reduces your blood pressure over time.
Cardiac Blood Flow
Your heart obtains blood from its own circulatory system. As aerobic exercise enhances cardiac strength, your heart requires a reduced blood circulation at rest. Conversely, exercise enhances cardiac blood flow during activity -- enabling greater exercise intensities.
Muscle Blood Flow
Muscle receives oxygen from the smallest blood vessels, known as capillaries. According to the book "Exercise Physiology" by George A. Brooks, Thomas D. Fahey and Kenneth M. Baldwin, an adult body contains more than 1 billion capillaries. Endurance exercise increases capillary density and improves material exchange between blood and muscle tissue.
References
- American Heart Association; Cardiovascular Diseases in the United States, 2009; American Heart Association and American Stroke Association
- "Anatomy and Physiology"; Kenneth Saladin; 2009
- "Exercise Physiology: Human Bioenergetics and Its Applications"; George A. Brooks et al.; 2004
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