The American College of Sports Medicine (ACSM) defines aerobic exercise as any activity that uses large muscle groups, can be maintained continuously, and is rhythmic in nature. It is a type of exercise that overloads the heart and lungs and causes them to work harder than at rest. Aerobic exercise include walking, jogging, jumping robe, bicycling it can be stationary or outdoor, skating and swimming.

BENEFITS OF AEROBIC EXERCISE

Strengthening the heart and cardiovascular system.

Improving the circulation and help the body use oxygen better.

Improving the heart failure symptoms.

Increasing energy levels so more activities can be done without becoming tired.

Increasing endurance and lowering blood pressure

EFFECTS OF AEROBIC EXERCISE ON CARDIOVASCULAR SYSTEM

The heart is a large muscular organ which constantly pushes oxygen-rich blood to the brain and extremities and transports oxygen-poor blood from the brain and extremities to the lungs to gain oxygen. Blood comes into the right atrium from the body, moves into the right ventricle and is pushed into the pulmonary arteries in the lungs. After picking up oxygen, the blood travels back to the heart through the pulmonary veins into the left atrium, to the left ventricle and out to the body's tissues through the aorta.

The heart becomes stronger and larger as a result of exercise so it can pump more blood through the body with every beat and sustain its maximum level with less strain. The resting heart rate of those who exercise is also slower because less effort is needed to pump blood.  Exercise uses up a lot of energy, which the cells derive from oxidizing glucose. Both glucose and oxygen have to be delivered by the blood. This means that the heart has to work harder to pump more blood through the body.

The cardiovascular system is the physical network composed of the heart and its connected arteries, veins, and capillaries. The cardiovascular system delivers oxygen and nutrients to every cell and removes the carbon dioxide and waste products made by those cells for disposal. When the body is subjected to exercise, and its increased physical demands, the cardiovascular system is forced to work more quickly and more efficiently to fulfill bodily needs and a number of physiological changes occur over time to this system through aerobic exercise.

During vigorous exercise the cardiac muscle of the heart will grow stronger over time, as the heart adapts to working harder during exercise. A stronger and more efficient heart reduces the resting pulse of the subject; as the heart strengthens, it does not have to beat as frequently as when at rest to achieve the same effect in the pumping of blood through the cardiovascular system. The greater flow of blood available to a person who regularly exercises tends to reduce the amount of low-density lipoproteins within the blood vessels that can form a harmful blockage known as plaque, a condition that tends to narrow the passage within each artery. Exercise does not make the arteries larger, but these vessels become more elastic through exercise permitting a greater and more beneficial blood flow throughout the body. As a result improving the ability of the cardio respiratory system to take oxygen from air inhaled into the lungs, and then load and transport it more efficiently. Greater efficiency in the movement of blood through the cardiovascular system permits greater amounts of oxygen to be transferred from the respiratory system; lung size does not increase due to exercise by any appreciable degree.

REFERENCE

Elaine N.M., 2009. Essentials of Human Anatomy & Physiology. 9th Ed.USA. Pearson International Edition.Page 363-367.

Roy.J.J, Gary. J. B.1999. Faculty of physical Education.[online].USA.Available from< http://circ.ahajournals.org/cgi/content/full/99/7/963>;[Retrieved 09 july 2010].

Peterson.D.M. 2009. Mayo Clinic Fitness Center [online].
Available from<;http://www.mayoclinic.com/health/aerobic-exercise/EP00002>;[Retrieved 13 july 2010].