Fuzzy Science: 3 Claims About Yoga That Just Aren't True
Have you ever been in yoga class and heard a teacher say, "The organs are like a dirty sponge, and we are ringing them out to detoxify the body?" Then you wonder, "Are we really? Does that really work?" My investigative and inquiring mind doesn't take these types of statements at face value. With a lot of reading and research, here are some things I've learned to be untrue about yoga, and the actual facts behind the practice.
The Myth: Yogic Breathing Increases Oxygen Intake
This one comes up often at the beginning of a class. When a teacher describes Ujjayi breath, we often hear, "This breath will deliver more oxygen to your body." The body already processes about 95-98% of the oxygen we take in. Our bodies are quite efficient at that. Altitude has a greater impact on our oxygen intake than whether we breathe deeply or slowly, and constricting the back of the throat has no impact on this whatsoever.
The value of ujjayi breathing, though, is not insignificant. Studies show slow, controlled breathing can increase the amount of carbon dioxide in the blood. The result is a dilation of blood vessels in the brain, and the body will re-route some oxygen that way. This can deliver a great sense of calm.1
What breathing practices do accomplish is to affect our ability to remain present in the class. Because the body has a natural, unconscious rhythm for breath, we will slip back into that rhythm unless we remain vigilant. On the other hand, there is no natural, unconscious movement of the body. Therefore, it is possible - and even likely - the body can learn a movement pattern and repeat it with little conscious awareness.
I often find myself out for a walk or run or even a drive and realize I haven't been paying attention at all for some time. The body can perform tasks it knows well on autopilot, and we run this risk in yoga class. By constantly returning to the breath to check in, we know whether we are truly present. If the breath slips away to an unconscious rhythm, we may be going through the motions of yoga without truly practicing.
The Myth: Yoga Can Be a Great Cardiovascular Workout
With the onslaught of "power yoga" in the West, many teachers have claimed yoga is a sufficient cardio workout. Some claim it isn't necessary to "do cardio" and practice yoga, and many even cite specific poses that will increase the heart rate significantly. I have heard teachers say performing shoulder stand "is almost like going for a run."
To increase cardiovascular health, you must achieve a heart rate of 80-85% of your maximum for at least twenty minutes. There is some debate over whether it is best to do twenty continuous minutes or to do interval workouts, but the twenty minute number has been consistent for sometime. Your maximum heart rate is 220 minus your age. For me, at age 29 (for three more months, and I'm sticking to it), the maximum is 191. My target heart rate (80-85% of max), then, is at least 153 to achieve cardiovascular benefits. Although not exact, this formula works for most people in most conditions. If you believe yoga can achieve this, I would encourage you to wear a heart monitor to class. Go ahead. Prove me wrong.
Thankfully, yoga is not meant to be a cardio workout. It is incredibly efficient at doing what it's designed for - increasing flexibility, muscle tone and strength, balance, focus, peace of mind, and health of the joints and back. It's okay by me if yoga is not all things to all people. So don't worry too much about making yoga your cardio workout. Just go for a run, and on another day do some yoga.
The Myth: Yoga Will Increase Your Metabolism
The "yoga body" is now world famous. Slim, bordering on skinny and boasting a fantastic rear end in some lululemon pants. The stereotypical yogi may give the impression that yoga is a great way to lose weight. I personally believe it is, too - but not because it raises your metabolism.
(By the way, I'm not suggesting this is somehow the "right" body-type, just that it is stereotypical for a yoga body. I believe the trend toward athletic feats in yoga, specifically the apparent obsession with handstands, is leading toward a more athletic and less slender build. I predict that will be the body of the future yogi.)
Here is the shockingly sorry news about yoga. Studies show yoga actually decreases metabolism. The emphasis on breath-linked movement, calm breathing, calm mental capacity, and overall meditative state actually slows the body's systems. Over time, a person regularly practicing yoga may actually lower his or her metabolism quite a bit.
Yoga has a built-in check-and-balance system for this metabolism-slowing effect, though. I call it "happiness." Perhaps the most promising research on yoga's effect on the body come from studies on mood changes. Overall, there is no denying yoga helps boost the mood and relieve stress. For most people, this will result in a natural tendency to lose weight and keep it off. So go ahead, practice yoga with no regard for what it will do to your metabolism. You'll be so darn happy you won't need that extra trip to the fro-yo machine.
1. William J. Broad, The Science of Yoga. Simon & Schuster, 2012.
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