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The standard workout arc, whether it’s a yoga class or Peloton session, is usually book-ended by two easier parts: the warm-up and the cool-down. Personal trainers insist on them, physiology textbooks tout them and most video workouts include them.
But for many people, just fitting in a 30-minute run or 25-minute strength session can feel impossible. Do you really need another five minutes to cool down?
The answer is, not really. A cool-down is typically some form of easier movement that acts like an offramp from a workout, allowing the heart rate and blood pressure to slowly recover to pre-exercise levels. For most people, that means jogging slowly after a hard run or stretching after weight lifting. But it could be as simple as a few slow breathing exercises.
While research has shown that as little as nine minutes of dynamic movement before exercise can reduce injury and make a workout more effective, there has been far less data supporting the cool-down, said Andy Galpin, the director of the Human Performance Center at Parker University in Dallas.
If you rush from your spin bike to your morning commute, you likely won’t sabotage your workout gains or recovery. But you could be missing out on other benefits.
What constitutes a cool-down?
“As a general rule,” said Dr. Erica Spatz, a cardiologist at Yale School of Medicine, a cooled-down state is “when the heart rate comes down below 100 beats per minute and breathing returns to normal.”
But there isn’t a specific protocol or definition of how to get there after exercise. Any activity that brings the body to a resting state could count, said Monika Fleshner, a professor of integrative physiology at the University of Colorado, Boulder.
A cool-down can be passive, like foam rolling or breathing exercises in the shower. But more often it’s active, such as continuing an exercise at an easier pace or going to a lower resistance on a spin bike. If you were lifting weights, you might perform a few mobility exercises after.
For the average person, a cool-down should take about five to 10 minutes, depending on the intensity of the workout, said Dr. Spatz.
Do cool-downs work?
When it comes to performance or injury prevention, the short answer is no. But that doesn’t mean they have no value.
For decades, experts prescribed an active cool-down to help alleviate muscle soreness by allowing built-up lactic acid to dissipate. But the lactic acid theory was debunked as early as the 1980s, and we now know the chemical has nothing to do with muscle soreness, though many people still buy into the concept, Dr. Galpin said.
A 2018 review found that active cool-downs are largely ineffective at improving same- or next-day performance and do not significantly reduce muscle soreness or damage. But that doesn’t mean you should skip cool-downs if you enjoy them, said the review’s co-author Bas Van Hooren, a sports scientist and assistant professor at Maastricht University in the Netherlands.
“Our review didn’t find any downsides to doing a cool-down,” he said. Some people reported that it felt good, or that they used it as a time to socialize, he added.
However, exercise can trigger a stress response and activate a fight-or-flight reaction in the body, Dr. Fleshner said. And while the body will return to a resting state on its own, a passive cool-down that focuses on slow, controlled breathing can activate a rest-and-digest response in some people, facilitating a quicker return to normal breathing levels, heart rate and blood pressure, she said.
When do you actually need a cool-down?
There are three scenarios where cool-downs are useful, if you enjoy them.
First, ramping down can be helpful for especially intense exercise. If you suddenly stop after a hard workout, your blood pressure may drop while your blood vessels are still dilated, causing you to feel dizzy, even faint, Dr. Spatz said. This is especially true among people 60 or older or those with heart disease.
Second, people experiencing chronic stress may also have a more sluggish return to a resting state, Dr. Fleshner said. “A cool-down that includes controlled breathing, like yoga or meditative stretching, might help them activate their parasympathetic nervous system” to calm the body, she said.
Lastly, if you exercise vigorously in the evening, especially at a high intensity, a cool-down may lead to a better night’s sleep, Dr. Galpin said. Levels of the stress hormone cortisol naturally increase in the morning and decrease at night, and moderate to intense exercise can elevate them, causing increased heart rates.
“Exercise is essentially a form of arousal, just like watching a thriller or playing a video game,” he said.
In addition to helping the body shift to a resting state, a cool-down can also be a time when you reflect on the work you’ve done, Dr. Fleshner said. The last thing it should be is an added stress.
“Is it essential? No,” she said. “Can it be nice? Yes.”
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