Learn whether yoga is good for weight loss and how yoga affects fitness.
In 2005 and 2007, two separate studies measured the metabolic rate of people taking a beginner yoga class and found a calorie burn of 2.3-3.2 calories per minute, about the same calorie burn as strolling through the mall--or about 104-144 calories in a 45 minute workout. At this rate, to burn one pound (or 3500 calories) of fat, you’d have to perform over 28 hours of yoga!
Does More Advanced Yoga Burn More Calories?
But wait! Isn’t it possible that people taking a beginner yoga class may burn fewer calories because they aren’t performing advanced movements or doing hot yoga at a high room temperature? In other words, could more difficult yoga routines burn more calories than a beginner yoga class or easier form of yoga (such as Hatha Yoga)?
It turns out that another 2007 study investigated that very question and measured the heart rate of participants performing a more vigorous form of yoga called Ashtanga Yoga. Researchers compared that type of more vigorous yoga to the same types of beginner yoga routines from the other studies I mentioned.
In the study, the heart rate during Ashtanga Yoga increased by over 30 beats from the resting heart rate, whereas the heart rate during the easier yoga sessions increased by only half that much, or about 15 beats.
Will Yoga Help You Lose Weight?
That may seem like a big difference, but when it comes to weight loss, a heart rate of just 30 beats over resting heart rate is not very significant. To put this in context, your heart rate can go 30 beats over your resting heart rate when you’re gardening, walking the dog, or vacuuming the house--and could increase by 15 beats per minute through the mere act of standing.
So although it’s true that an increase of 30 beats over resting heart rate will certainly improve cardio respiratory fitness, an increase of this small magnitude is simply not going to give you much bang for your buck when it comes to weight loss and won’t get your house as clean as vacuuming will.
Will Hot Yoga Help You Lose Weight?
But perhaps you’ve had friends tell you about their invigorating hot yoga experience, or heard about incredibly difficult hot yoga in the news. Surely, that must burn more calories! In hot yoga, or Bikram Yoga, the temperature in the yoga room is turned up higher than 105 degrees, with a recommendation of at least 40 percent humidity. As a result, people taking a hot yoga class experience more fatigue, a higher heart rate, and a significantly greater amount of exhaustion (not to mention body odor).
But this relatively higher amount of perceived exertion is not really due to the fact that people are burning more calories. As a matter of fact, by simply walking into a hot room and standing for 45 minutes, your heart rate will significantly increase. That is because your body’s primary mode of cooling is to sweat and to shunt blood to your extremities. As you sweat, you lose blood volume, and as you shunt blood, your heart has to work harder to deliver that blood. And as a result your heart rate increases.
But the increased heart rate is not due to you moving more muscles or burning more calories. It’s simply your body’s environmental, temperature-regulating response to hot conditions, and the only significant weight you’re going to lose in a hot yoga class is water weight. For more on temperature and the body’s calorie burning reaction, check out this article by the Nutrition Diva: Does Air Conditioning Make You Fat?
Yoga and Your Metabolism
Could it be that yoga may actually slow your metabolism? In fact, a 2006 study measured the metabolic rate of yoga people vs. non-yoga people, corrected for body weight, and found a 15% lower metabolism in the yoga group. To put this in context, that means that if you normally burn 2000 calories at rest, you might lower that calorie burn to 1700 calories at rest if you take up yoga.
That is because yoga is a relaxing activity, and actually slows down your body’s “fight-and-flight” reactions, also known as your sympathetic nervous system. Although this is highly beneficial for extending your life span, controlling stress, and making you feel good, it’s certainly not going to shed any pounds.
Once again, I have to emphasize that I have nothing against yoga and I do some form of it nearly every day to improve my flexibility, balance, and relaxation. However, when it comes to calorie burning for weight loss, yoga is really one of the least effective modes of exercise. But before I am struck with lightning by the yoga gods and goddesses, let me express one final thought: if the practice of yoga gives you a greater mental discipline and body awareness, and you use those benefits to motivate yourself to exercise, then yoga may indirectly be beneficial for weight loss.