By the end of each morning's workout, I'm not just exhausted -- I'm in a mad rush. The kids are up and require feeding and changing, I need a protein shake and a shower, my hour-long freeway commute beckons, and my Blackberry is buzzing with work emails. Every minute -- every second -- counts. But as I near the end of my first round of P90X, it's become increasingly difficult to drag my butt out of bed to squeeze in an hour-and-a-half of Tony Time before the day's craziness commences. How, then, can I reduce my workout time?
Cut out the cool-down.
I warm up without fail, but by immediately turning off the DVD player when the cool-down starts, I save about five minutes every morning (30 minutes each week!) -- enough time to make my shake and get the kids dressed, or to quickly jump in and out of the shower. And according to the experts, this is perfectly fine because cool-downs are an utter waste of time.
As Gina Kolata wrote in the New York Times last week:
[T]he cool-down is enshrined in training lore. It’s in physiology textbooks, personal trainers often insist on it, fitness magazines tell you that you must do it -- and some exercise equipment at gyms automatically includes it. You punch in the time you want to work out on the machine and when your time is up, the machine automatically reduces the workload and continues for five minutes so you can cool down.
The problem, says Hirofumi Tanaka, an exercise physiologist at the University of Texas, Austin, is that there is pretty much no science behind the cool-down advice.It's not even clear "what the cool-down is supposed to do," writes Kolata. "Some say it alleviates muscle soreness. Others say it prevents muscle tightness or relieves strain on the heart." But actually,
Exercise researchers say there is only one agreed-on fact about the possible risk of suddenly stopping intense exercise. When you exercise hard, the blood vessels in your legs are expanded to send more blood to your legs and feet. And your heart is pumping fast. If you suddenly stop, your heart slows down, your blood is pooled in your legs and feet, and you can feel dizzy, even pass out.So where did everyone get the idea that cooling down is a critical part of working out?
But does it matter for the ordinary, average athlete? “Probably not a great deal,” Dr. Thompson said. And, anyway, most people don’t just stand there, stock still, when their workout is over. They walk to the locker room or to their house or car, getting the cool-down benefit without officially “cooling down.”
The idea of the cool-down seems to have originated with a popular theory -- now known to be wrong -- that muscles become sore after exercise because they accumulate lactic acid. In fact, lactic acid is a fuel. It’s good to generate lactic acid, it’s a normal part of exercise, and it has nothing to do with muscle soreness. But the lactic acid theory led to the notion that by slowly reducing the intensity of your workout you can give lactic acid a chance to dissipate.Cooling down feels good, and when I have all the time in the world (which is never), I try to do a few "world-famous" Karen Pot Stirrers" and some hamstring and quad stretches. I love "Huggers" and "Reachers" like you wouldn't believe. But after reading this article, I'm happy to skip the last few minutes of each P90X video -- especially when there are more pressing matters at hand, like eating or pooing.
Yet, Dr. Foster said, even though scientists know the lactic acid theory is wrong, it remains entrenched in the public’s mind. “It’s an idea we can’t get rid of,” he said.
In fact, Dr. Tanaka said, one study of cyclists concluded that because lactic acid is good, it is better not to cool down after intense exercise. Lactic acid was turned back into glycogen, a muscle fuel, when cyclists simply stopped. When they cooled down, it was wasted, used up to fuel their muscles.
As far as muscle soreness goes, cooling down doesn’t do anything to alleviate it, Dr. Tanaka said. And there is no physiological reason why it should.