Dear ankita,
The word aerobic literally means "with oxygen" or "in the
presence of oxygen." Aerobic exercise is any activity that
uses large muscle groups, can be maintained continuously for
a long period of time and is rhythmic in nature. Aerobic activity
trains the heart, lungs and cardiovascular system to process and
deliver oxygen more quickly and efficiently to every part of the
body. As the heart muscle becomes stronger and more efficient, a
larger amount of blood can be pumped with each stroke.
Fewer strokes are then required to rapidly transport oxygen
to all parts of the body. An aerobically fit individual can
work longer, more vigorously and achieve a quicker recovery
at the end of the aerobic session.
Examples of aerobic exercise:
Aerobic dance, aerobic machines, backpacking, ballroom
dance, basketball, belly dancing, boxing, broomball,
calisthenics, canoeing, cycling, fencing, Frisbee, golf,
gymnastics, handball, hiking, hockey, ice skating,
jazzercise, jogging, judo, jumping rope, karate,
kayaking, mountaineering, racquetball, rock climbing,
roller skating, rope climbing, rowing, running,
skateboarding, skiing, skin diving, spelunking, square
dancing, squash, step aerobics, swimming, walking, water
skiing or any other activity that meets the criteria in
section
Anaerobic exercise is complementary to aerobic exercise. The early stage of all exercise is anaerobic.
Anaerobic literally means "without air", and refers to the energy exchange in muscles during short high intensity workouts. Anaerobic exercise is one where anaerobic metabolism is taking place. In a long exercise the glycogen supply local to the muscle runs out and the body converts to aerobic metabolism; when aerobic metabolism is sustaining the workout it is an aerobic exercise.
During the anaerobic phase, energy is released and made available to muscles by converting immediately available sugars in the blood to lactic acid. In the following aerobic phase, a more slowly available oxygen supply is required, enabling the lactic acid to be broken down to carbon dioxide and water, releasing larger amounts of energy.
Examples of anaerobic exercise include heavy weight lifting, sprinting, and jumping; any exercises that consist of short (roughly no more than 3 minutes, typically a few seconds) exertion is an anaerobic exercise. Most anaerobic exercises are performed in sets. Anaerobic exercise is typically used by athletes in non-endurance sports to build power and by body builders to build muscle mass.