Aerobic exercises are those exercises or activities that use large muscle groups, can be maintained continuously, and is rhythmic in nature. Aerobic exercises increase your endurance. Aerobic exercises also burn fat. Examples of aerobic exercises or activities include: walking, bicycle riding, swimming, running, weight lifting or weighted exercises when you do not rest between sets, dancing (all types), gardening (especially raking leaves), jumping rope, stair climbing, and of course aerobics. Walking is probably the easiest to do and you can adjust your walking to many different levels.
Anaerobic exercise is an exercise that for short brief intervals you put out maximum/intense effort. Anaerobic exercises build strength (muscles and bones) and increased speed and power. Anaerobic exercises include bodybuilding/weight lifting, sprinting, tennis, and jumping. Anaerobic exercises burn carbohydrates rather than fat. You still lose weight with anaerobic exercises; however, the muscle mass you gain weighs more that fat, so in actuality you may be trimmer, but weigh more.
Most athletes use a combination of both aerobic and anaerobic exercises to train for their respective sports. This doesn’t mean that you can’t as well. Doing a little of both types of exercise will make you an overall fitter person, regardless of your age. An example of a combination exercise program, would be walking three times a week, and doing some weight machines two or three times per week.