A warm-up is important for many reasons. Some of these reasons include: - Facilitates transition from rest to exercise-Stretches postural muscles-Augments blood flow-Ele … vates body temperature-Allows body to adjust to changing physiologic, biomechanical and bioenergetic demands placed on it during conditioning phase. warm-up helps your body prepare for any physical activity. Without a warm-up, your muscles will be cold and stiff, the oxygen won't be flowing to your muscles and joints and you will not perform the activity well. Also, when you do a warm up your recovery from exercising will be more comfortable and shorter.