Many people start to exercise with the desire to lose weight. In reality, your body is designed not to expend too much energy while performing a physical activity. Imagine that you had to eat a cheeseburger between every couple of squats. You would go insane. Biologically, therefore, your body is designed to run a marathon on a couple of bananas and some water. This efficiency is in the interest of your survival. Exercise, therefore, is meant to serve a different purpose. You exercise to enlarge the capacity of your lungs; to strengthen the muscles of your heart and the muscles of your body. Cumulatively, this has a positive impact on metabolism. All exercises do not have the same impact and understanding the nature of your training is useful.
Isometric exercises are those where you contract your muscles but do not move your joints, for example, flexing your biceps. Such exercises have long term benefits on your muscles but little effect on your cardiovascular system. Isotonic exercises require contraction of muscles and movement of joints together for e.g. weight lifting. These exercises help you build muscle strength and depending on intensity impact on your cardiovascular system. Isokinetic exercises make you undergo both weight lifting and an entire range of motions for example circuit training. This form of exercise build both your muscles and also gives you a cardiovascular workout.
An Anaerobic exercise is performed without using the oxygen that you are breathing for e.g. sprinting for one minute. Such activities cannot be carried out for long durations and are usually complemented with some form of aerobic exercise. Aerobic exercise where you require large quantities of air for prolonged periods and force the body to improve the systems needed for transportation of oxygen for e.g. swimming or running. The benefits of this form of exercise are that it increases the volume of blood, the capacity of your lung and make your heart muscles stronger.
Pick your exercise wisely or even better try all of them. What ever you do, remember to include stretching into your routine.