You’ve probably heard it so often that you take it for granted: You should warm up and cool down as part of your workout. And, yet, you’ve probably skipped these two fundamentals more often than you’d like to admit. Yeah, we know: You had to get back to the office, pick up the kids or get home on time. You figured you’d devote your limited time to the “main” workout because that easy stuff before and after it was expendable, right?
Wrong. The truth is, the warm-up and cool-down are essential parts of your fitness regimen. And once you understand the full extent of their physiological benefits – such as increased performance, easier effort and lowered risk of injury – you’ll be far less likely to skip them.
The warm-up primes the body for exercise and lets you get the most out of your workout with a minimum of discomfort. Afterward, a cool-down optimizes recovery and lets your body wind down safely.
“It’s hard on our bodies to start and stop abruptly,” says Derk Voskuil, a personal trainer and metabolic specialist with Life Time Fitness. “We’re a biological system. We can’t turn on instantly like a drill.”
Warm-Ups: Priming the Pump
Jumping into exercise without warming up causes a sudden hike in blood pressure, stresses the heart, makes us feel breathless and increases the risk of injury. Taking the time to begin with light cardiovascular exercise allows you to process oxygen more efficiently and accumulate less lactic acid, and permits your muscles and nerves to fire better.
Short on time? Voskuil recommends that people cut short the main workout, not the warm-up. “It’s not about coming in and working yourself to death,” he says. “If you slowly progress into your workout, you’ll notice things happen a little easier because you’re allowing body chemistry to work as it’s designed.”
Warmer Is Faster – “Warming up” is a universal expression for getting ready, whether we’re talking about an athlete or an engine – and for good reason. Higher temperatures speed chemical reactions and make parts move more easily. An increase in muscle temperature improves mechanical efficiency, makes contractions more rapid and forceful, and makes muscle fibers less stiff. Consequently, exercise feels better and produces better results.
Increased Blood Flow – Warming up increases your heart rate and circulates freshly oxygenated blood through the body. As a result, harder efforts don’t shock the system.
At rest, our bodies store about two-thirds of our blood in the venous system. Light exercise causes arteries to dilate and increases blood flow into the muscles. At the same time, the contraction of large muscles and constriction of veins add a pumping effect that sends blood back to the heart at a moderate rate. Sudden exercise, by contrast, doesn’t give the body’s systems a chance to adjust. As a result, it places excessive strain on the heart, even among people who are physically fit.
“Warming up provides cardiovascular protection,” says Carl Foster, PhD, a professor in the Department of Exercise and Sport Science at the University of Wisconsin-La Crosse. He cites one study in which UCLA researchers took a group of physically fit firefighters and had them run hard on a treadmill from a cold start. “Their electrocardiograms looked the same way as it would if they had heart disease,” Foster says. “But if you put them on the treadmill after warming up, that effect went away.”
Increased Muscle Metabolism – Enzymes work optimally at a temperature slightly above the normal resting temperature. A warm-up allows your body to ramp up aerobic-energy production. If you begin too abruptly, your body may draw on the anaerobic-energy system, which is why a cold start may initially leave you feeling breathless.
“One example is the ‘second wind’ when running,” says David Behm, PhD, a professor at the School of Human Kinetics and Recreation at Memorial University of Newfoundland. “When you go for a run, often during the first few minutes you feel very tired, but after three to five minutes your energy level picks up again. The enzymes weren’t ready for exercise and were cycling slowly. To provide enough energy, you had to dip into your anaerobic sources.”
Better Oxygen Delivery – A warm-up allows you to process oxygen faster. Heating the blood a few degrees allows for greater release of oxygen from hemoglobin and myoglobin and thus enhances its delivery to the muscles.
Faster Reactions – Studies have demonstrated that a rise in body temperature increases the speed of nerve impulses, which is especially important in tasks requiring complex movements or rapid reaction. A process known as “Treppe,” or “staircase phenomenon,” occurs when a muscle contracts more forcefully after it has done so a few times; muscles require decreasing amounts of stimuli for repeated contractions. In short, a warm-up helps put you in the zone, where you can hit everything from your running stride to tennis balls with greater ease.
Increased Pliability – Increasing body temperature makes muscles and joints more flexible and less prone to injury. A warmer muscle is more pliable and has greater range of motion. Similarly, joints move more easily: One study showed that mild warming decreased resistance in the metacarpal joint by 20 percent.
Well-Lubricated Joints – Warming up effectively gives your joints a lube job. It increases synovial fluid production, making your joints move more easily and reducing the chance of injury.
Body-Mind Benefits – A gradual start gives your brain and body a chance to get on the same page. A warm-up also provides a psychological boost that gets you ready to perform. One 1961 study published in Research Quarterly for Exercise and Sport found that improvements made in a timed cycling test disappeared when subjects were hypnotized to “forget” they had warmed up.
Cool-Downs: Controlled Descent
During your workout, it was rush hour in your body. Now imagine that those fast-moving cars hit gridlock traffic. This is what happens when you suddenly stop vigorous exercise: Blood pools in your extremities, waste products aren’t eliminated quickly (leftover adrenaline in your bloodstream can put stress on your heart), and your body temp remains elevated enough to make you overheat. A gradual cool-down will leave you feeling refreshed and ready for your next workout.
Decreased Pooling Of Blood – When you slam on the brakes after a workout, blood accumulates in the muscles. Your heart rate remains elevated, but the pumping effect of the muscles sending blood back to the heart ceases.
“Now it’s hard to get that blood back up to the heart and brain,” says Behm. “Some people may get dizzy or pass out if they stop too abruptly.”
Or worse. At-risk people may suffer arrhythmias or even heart attacks. Foster warns: “If you get a lot of pooling and your blood pressure drops, you’re at risk for a cardiovascular catastrophe.”
A Jump On Recovery – Light exercise keeps blood flowing to and through your muscles and allows your body to more quickly eliminate waste products such as lactic acid. Your body also begins protein resynthesis and replenishes glycogen more quickly.
But let’s dispense with one myth: A cool-down won’t help you escape the aches of delayed onset muscle soreness (DOMS). One common misperception is that DOMS is caused by lactic acid pooling in the muscles, but research has shown this to be untrue and places blame instead on the microscopic tearing of muscle fibers and connective tissues, commonly caused by eccentric exercise (or braking-type movements).
System Clean-Out – Moderate and hard exercises cause your body to pump out hormones like adrenaline and noradrenaline in order to increase heart rate, blood pressure and breathing, and to break down glycogen. An easy cool-down helps your body clear these hormones from your system and return to a resting state more quickly.
Temperature Check – A cool-down literally drops your body’s temperature. Moving around helps dissipate heat into the air. A gentle jog or walk has a fanning effect because it allows moving air to carry away the heat.
OK, so now you know why you keep hearing all that advice about warming up and cooling down. But even if you can’t remember all the technical details, remember this: The few minutes you save in skipping a warm-up and cool-down are heavily outweighed by the decreased returns from your workout. Taking the time to ease your body in and out of exercise will ultimately pay bigger dividends. And that’s a wise investment in both your fitness and your health.