We’ve all done it now and again; Stepped off the treadmill, or racked our weights and wandered straight out to the car with no cool-down. Why? Why do we do it?! Cool-downs, like warmups are essential to your workouts- some may argue that cool-down is even more important than warmups. Here’s why:
When muscle tissue is engaged in hard work, the body floods the area with blood to satisfy the oxygen demands of the activity. The delivery continues until the activity stops. When exercisers engorge the large muscles of the lower body with blood and then do not follow with a cool down of lighter rhythmic activities, the blood remains in the tissue. When this occurs, blood can build up around valves, a condition called blood pooling. The fluid is deoxygenated and high in bicarbonate and other byproducts of exercise metabolism. Due to the fact that approximately 64% of all circulatory blood is located in the systemic veins, transitioning the body from heavy work to rest may impede upon blood flow back to the heart. Blood pooling shunts the needed blood away from the heart, which can cause acute ischemia in the tissue and a reduced cardiac output. Blood pooling is often identified by leg heaviness and discomfort, which often makes sleeping difficult.
Blood pooling can be avoided if exercisers routinely engage in cool-down activities following training. Light aerobic exercise increases the flow of blood back to the heart due to the venous mobilization caused by rhythmic muscular contractions. This begins to restore the body to pre-exercise condition. The activity increases by-product removal and conversion, including lactic acid, and sets up the tissue for more successful recovery. Elderly individuals or those with peripheral vascular problems should use longer warm-ups and cool-downs to better regulate blood flow, as older or damaged veins have a reduced capacity to return blood to the heart on their own, and an immediate cessation of activity can have negative effects on the vascular system.
The cool-down should use low intensity, rhythmic, large muscle group exercise activities immediately following the exercise bout. The physiological rationale for the cool down includes the following:
- Reduction of blood and muscle lactate.
- Prevention of blood pooling.
- Promotion of venous blood return, which positively effects cardiac output.
- Reduced concentration of catecholamines in the blood.
- Reduced risk of cardiac irregularities post-exercise.
Cool-downs should be employed following both moderate to high intensity anaerobic and aerobic exercise. The actions promote a continued delivery of oxygen to the tissues that were placed under stress, which may aid in reducing delayed-onset muscle soreness related to cellular ischemia and tonic muscular spasm. Additionally, the prevention of blood pooling and the gradual decrease in activity enhances myocardial oxygen delivery and venous blood return to the heart, thereby promoting cardiac output. Although the primary activities should be of light aerobic nature, flexibility exercises can also be utilized at the end of the cool down to further promote a more relaxed state and take advantage of the warm tissue.
*Information gathered from: Advanced Concepts of Personal Training- Brian D. Biagioli