Breathing is something we take for granted. But during exercising, we can often forget to breath properly. What often happens is that when we contract a muscle, you hold your breath. When you hold a contraction for a count of 10, you may tend to hold your breath for a count of 10 too. Try to think about breathing, to make it a conscious action. If you make a conscious effort to breath, you'll be filling your lungs with air and your blood with oxygen, and that is good for the body. Always exhale on the hardest part of the exercise and inhale on the easy part. For example, sit-ups, when you contract your stomach muscle, and lift your head and shoulders off the floor, EXHALE. As you release the contraction and roll back to the floor, INHALE. If you are use weights, exhale an you lift and inhale and you lower. A good basic tip is always exhale on the hardest part of the exercise and inhale on the easy part. An example, let's say you're lying on your side ready to do leg raises. Exhale as you lift your leg and inhale as you lower your leg. No matter what type of exercise you are doing, always remind yourself to BREATH.