Why it is necessary to do warm-up and cool-down exercise before and after every workout session?
Warm up exercises prepares the cardiovascular and musculoskeletal systems of your body for the exercises. Warm up increases the blood flow and warms up the body. Without a warm-up, you can be easily prone to injury
Cool down exercises reduces muscle stiffness and soreness. Cool down exercises prevent the dizziness, which can happen if you suddenly stop exercising
Hello,
Apart from the above benefits, a good warm up can help in channelizing the oxygenated blood from other parts of the body to the muscles. This can help in preparing the muscles for workout. While cool down exercises can help in redistributing the flow of blood to the entire body.
You might find these two links beneficial:
http://www.mydr.com.au/sports-fitness/warming-up-and-cooling-down-for-exercise
http://www.americanheart.org/presenter.jhtml?identifier=3039236