The Importance of the Warmup and Cooldown
Question: “I fit my aerobic workouts into a very tight schedule. How important is it to spend time warming up before and cooling down after exercising? I often do neither.”
Warming up prior to engaging in more vigorous exercise serves several important functions. From both a mental and physiological standpoint, it prepares the body for action. Heart rate speeds up and promotes increased blood flow to the muscles. Muscle temperatures become elevated, which allows for improved muscle contraction, quicker reflex time and greater suppleness. This also lessens the probability of subsequent muscle and connective tissue injury.
How important is the warmup? It depends on the intensity of the workout to follow. A thorough warmup is essential when you are planning to exercise at a relatively high intensity level for a sustained period. I do not feel the warmup is quite as important when the workout to follow consists of only light activity such as brisk walking or low-intensity stationary cycling. Most of my workouts fit into the low intensity category, and I often skip a formal warmup for the same reason you mention: lack of time. I might stretch a bit before I take a long walk with my dog, but that is about it. To my knowledge I have not experienced any ill effects from my infrequent and/or abbreviated warmups, but again, my workouts are typically performed at a relatively low level of intensity. However, I do believe, as do most major health and fitness organizations, that it is prudent to undergo a thorough warmup prior to engaging in physical activity that substantially raises heart rate and imposes a relatively high degree of physical stress on the body.
A dynamic warmup typically involves movement patterns that are somewhat similar to exercises performed in the workout. Activities that elevate heart rate such as jogging, jumping jacks, or pedaling a stationary bike can be supplemented with dynamic stretch movements such as lunges, leg swings and side shuffles. Dynamic stretching also increases heart rate and promotes blood flow which further prepares muscles, tendons and ligaments for the workout.
In many respects, the post-exercise cooldown may be more important than the warm up. The greater the physical demands of the workout, the more important it is to cool down afterwards. During cooldown, our physiological systems have an opportunity to gradually return from elevated exercise levels to more normal and stable levels, a physical state commonly referred to as homeostasis. Abrupt cessation of vigorous exercise without the benefit of a cooldown can result in cramping, pooling of blood, circulatory problems and slowed removal of cellular waste products. In rare instances, it can lead to more serious health issues. For example, vigorous aerobic exercise has been shown to trigger release of the hormone norepinephrine. Elevated levels of norepinephrine can make the heart more susceptible to arrhythmia, a potentially fatal rhythm irregularity. During cooldown, levels of norepinephrine can gradually return to within normal limits.
An active cooldown consisting of low-intensity aerobic activities such as brisk walking or slow jogging will decrease heart rate, lower blood pressure and return core body temperature to within normal limits. Performing mild aerobics after a strenuous workout also helps to circulate cellular waste products so that they do not accumulate in the muscles. This is an important function as waste products that build up in the muscle can cause soreness and fatigue that may carry over to your next workout. Once heart rate has returned to near resting level, you can address the specific muscles and muscle groups that bore the brunt of the activity. Depending on the nature of the workout, these muscles may include the hamstrings, quadriceps, back, neck and shoulders. Muscles can become tight and fatigued after intense exercise, so a few minutes of static stretching at the conclusion of the cooldown can alleviate sensations of tightness and next day soreness. Static stretch exercises slowly extend the muscle or muscle group to its greatest possible length without discomfort and maintain that position for about 30 seconds. Stretching after a workout may do more to extend the length of your muscles and improve flexibility than stretching before the workout. Due to the warmth generated by increased blood flow, your muscles typically have greater extensibility post-exercise than they do pre-workout.
I understand that it can be difficult to squeeze regular workouts into a busy schedule, and adding a cooldown afterwards makes it even tougher. Keep in mind that a cooldown of light aerobics coupled with stretching exercises can be accomplished in only 10 minutes or so. If you can routinely include a cooldown as part of your workout, I believe you will find it time well spent.