The Mild to Moderate Physiological Benefit of Asana
We all know that yoga, including Ashtanga yoga, is good for us. But how good?
As it turns out, not sooo good. Physiologically at least, asana practice provides only “mild to moderate” physiological benefits. What do you think, Ashtangis?
For me, I’d agree. Here are the results from a study I conducted during a recent Mysore-style class:
- My heart rate averaged 104 beats per minute and I was in my heart rate zone for only 14 minutes in a 75 minute practice (through Navasana). I burned 104 calories.
- During my traditional exercise program of 45 minutes cardiovascular training and 15 minutes exercising, my average heart rate is 135 and I burn 300 calories.
Sally E. Blank from Washington State University Spokane conducted a real scientific study (of Iyengar yogis - I know what you’re thinking) recently and categorized yoga as “mild to moderate intensity exercise without evidence of a sustained cardiopulmonary stimulus“.
The study is one of the few I’ve seen that actually quantifies the physiological benefits of any form of yoga, and I think it’s pretty interesting. Some of its findings include:
- In a 90-minute practice, the participants burned 100-200 calories.
- Participants were in a fitness heart range for 11-60 minutes in a 90-minute practice (or 55-85% of maximum heart rate).
- Standing asana, inversions and back bends (pushing up to back bends) resulted in the larger physiological response than seated or supine asana.
- Backbend and Warrior postures resulted in the highest heart rates.
- Alignment affected the participants’ ability to maintain backbend with perfect alignment resulting in holding backbend for 90-120 seconds while malaligned backbenders only held the posture for 60 seconds.
- Poor alignment raised blood pressure in many postures, but especially in backbend.
Some of the conclusions of the study were:
- “The general cardiorespiratory responses to asanas were similar to changes observed in subjects who perform weight lifting circuit exercise.”
- “This volume of exercise meets the current public health recommendations for physical activity that provides substantial benefits for reduced risk of cardiovascular disease and improved cardiovascular fitness for sedentary adults.”
- “Steady state heart rate was not sustained for a minimum of 10 minutes during the yoga practice.”
- “Moderate to strenuous yoga vinyasa and jumpings would be expected to promote cardiovascular endurance if the practice was sufficiently long. To achieve optimal cardiorespiratory benefits, the American College of Sports Medicine recommends that exercise include 20-60 minutes of large muscle rhythmic and dynamic activity with a minimum of 10 minutes of activity per session.”
- “Based on this evidence, yoga asanas can be fully integrated into western approaches to exercise prescription for healthy, rehabilitating, and diseased populations. “
The participants in the study were all women, aged 36-49 with a weekly practice of 4-9 hours per week and had practiced Iyengar for 2-16 years. In the study, the yoginis held poses for up to 5 minutes (with no vinyasa between poses). The yoginis did 24 postures over about 1-1/2 hours and were considered “intermediate” level practitioners.
The study also noted that at least 16.5 million people in the United States practice yoga and 77.1% are women.
Physiological Responses To Iyengar Yoga Performed By Trained Practitioners by Sally E. Blank at Washington State University Spokane was published in the February 2006 issue of the Journal of Exercise Physiology.
Thank you to Kelly McGonigal, a yoga therapist in the San Francisco Bay Area, for her exhaustive list of studies on the benefit of yoga.
And to SeaOfClouds for the heart photos.
And, Ashtangis, don’t forget to get your cardio in!
Olli said,
July 12, 2006 at 4:04 am
There must be many other things under title “physiological benifit” than just cardiovascular endurance. In that broader sense, I would say yoga’s physiological benifits are much above moderate. I can feel it in my everyday life. Anyway, yoga was here well before heart rate monitors. Also, by cutting calory intake one doesn’t have to burn those so hard. A nice way to save money and effort :).
Cheers,
Olli
susan said,
July 12, 2006 at 7:18 am
Now, I have taken Iyengar classes. I feel like there is NO comparison. I didn’t break a sweat. Nothing, unless the room was warmed up! If they meet the public exercise requirements, surely ashtanga would place higher on that scale. I think we are comparing apples and oranges here.
My main concern is that I don’t think that modern scientific research has even skimmed the surface of what yoga practice can do physiologically. Again, with modern scientific studies they try to break down one aspect of the whole. I am just not sure that “getting your cardio” is the way to optimum health and well being. Strength, flexibility, and endurance are together what make a healthy person. Not to mention diet and lifestyle.
tracy said,
July 12, 2006 at 2:57 pm
Wow. Ollie and Susan, you both sound so defensive. What is the big deal?
The point of the study is to MEASURE and be scientific, not simply go on what we each personally feels, which is not scientifcally measurable.
Cardiovascular fitness is very important to maintaining overall, long-term health. That is a well-known fact.
The study and our post doesn’t say that diet or lifestyle or stretching or the effect on one’s chakras (or whatever) is not important. It merely says that yoga doesn’t provide a tremendous cardiovascular benefit.
Also, any individual’s sense of “fitness” really has to do with where she is when she starts her practice. Most people do nothing, then start yoga, so of course, they should feel great when they start any kind of physical activity. However, my personal trainer - a competitive athlete - does not feel all that much greater after yoga. He is just * that * fit. His “feeling” is that yoga does not add to his fitness level or overall sense of well-being, which is simply off the charts.
susan said,
July 12, 2006 at 4:55 pm
I am not defensive. But you are being pretty definitive with this study based on Iyengar yoga. I ain’t talking chakras or whatever. I am not talking feel goodie new agey stuff.
My point is APPLES VS ORANGES. Iyengar apples to ashtanga oranges.
They are completely different.
Also, yeah cardio is proven to be good for you. But I think that
the measure of general health and well being may be redefined,
a bit like they have redefined the food pyramid.
philippe said,
July 12, 2006 at 5:46 pm
Hey Tracy, can you describe what you used to measure your heart rate and figure out the calories you burnt during practice?
ralph craig said,
July 12, 2006 at 8:16 pm
I don’t think this sheds any light on ashtanga practice. It’s the same reason Nancy Gilgoff who’s been doing Ashtanga for 30 years and has Iyengar training says that the two should never be mixed. The Vinyasas of Ashtanga creates a heat (be it internal or external) that gets and keeps you moving. Holding a pose for 1 min or whatever and no movement is different from the Ashtanga 5 breaths (25 to 50 if ill) and constant movement.
No defensivesness here, just pointing it out.
I wonder if the person who did the study could conduct one of Ashtanga and report back, I’m curious now. I’m naturally thin and don’t eat much-so I don’t worry about cardio and what not.
Dipita said,
July 12, 2006 at 9:56 pm
To add to the heat of this conversation, I want to point out that in the west the scientific data is carried to an exterme. Most doctors around the world would recommend a fairly moderate cardio as healthy. You don’t have to be running marathons every few months to be considered healthy! According to my experience and seeing those Ashtangis who’ve been around for a while, I seem to think that this morderate cardio is sufficient to be healthy. I think the west carries too far the minute details of how many calories you eat, you burn etc to the point where even living a happy life becomes stressful to some because they have over-eaten beyond their caloric intake or they haven’t done enough cardio etc. Most ashtangis I have encountered just do Ashtanga yoga as their primary form of physical endurance/training and they seem to be quite healthy to me. They are not over-weight, most seem to have enough endurance to go thru an intense practice of 1 1/2 or 2 hours with intense breathing.. My personal experience after doing Ashtanga yoga daily 6xweek for over 2 years is that I am more in shape and fit now than I probably was when I was training for my marathons - I mean more in shape both physically and mentally. I personally feel that several times the reason the cardio ratios become important is because of the level of stress that the person goes through: Ashtanga yoga helps eliminate this stress by focusing on what’s important - internal cleansing, purifying and mental cleansing, not external beautfiying.. So overall, I feel that there are no comparisons to be made between Ashtanga Yoga and other forms of physical exercise because alot of data (mental cleansing, calming effect etc) is not captured during the physical comparisons. I think a more accurate comparison would be to see the long-term effects on both physical and non-physical levels of doing Ashtanga yoga say 6 x week and doing some aerobic exercise like running 6 x week - over a period of 30+ years so that the overall data of how the body does physiologically and psychologically can be compared, not just calorie counting.
Lauren said,
July 13, 2006 at 7:18 pm
Stop the madness.
Word.
Controversial article - Ashtanga Diary said,
July 14, 2006 at 7:53 am
[...] I don’t read the Ashtanga News blog as much as I’d like to, but this article caught my attention because of my interest with fitness. The Mild to Moderate Physiological Benefit of Asana article caused a little controversy as you can see in the comments, 8 comments so far, ok, so that’s not so many compared to some 100+ comments I’ve read in other blogs I frequent (non-Ashtanga blogs), but definitely more than I get for one of my uninteresting, whinging posts about “oh poor me, I can’t do [insert asana name] because bla-bla-bla…”. Anyway, back to the topic on hand. [...]
ahu said,
July 15, 2006 at 2:18 am
Uhh I don’t know about this scientific results. From my own personal experience, I had been a cardio junkie for a long time… and then suddenly I dropped all that and began Mysore Self-practices daily and now I am fitter and stronger than ever! And also, I don’t think I could go through this tough year without therapy if I were not practicing ashtanga, it made me so much grounded!
well… this is my personal experience…
a
tracy said,
July 16, 2006 at 11:35 am
Hi all,
Philippe was curious about how I measured my heart rate, calorie usage etc.
I use the Polar heart rate monitor (http://www.polarusa.com/default.asp). Polar is one of the original manufacturers and is supposedly super good quality. I’ve had mine since 2001 with no problems and used it to lose more than 20 lbs. of fat a few years ago.
I bought it at Sports Basement in San Francisco, which also has an online store (http://www.sportsbasement.com/).
Eugene said,
July 16, 2006 at 8:45 pm
Yoga, American style… at least by 99% of the “yoga” people. Why are you so interested in the physical aspect of yoga?
Read Iyengar’s Light on Life. When asked if Pranayama promotes longevity, Iyengar answered, “Why bother? Your body will grow old no matter what.”
Have you seen any person who has lived forever? Even Guruji looks much older than he was 20 years ago.
Why heart rate is import in a yoga website? Why do you care about calories? Have these has anything to do with yoga?
vajrabhairava said,
July 21, 2006 at 1:09 am
it’s such a shame that no real studies are done of yoga… this sort of “exercise science” thing is so disappointing… i for one would like to see proper data on the respiratory effects of ujjayi (confirming, perhaps, the earlier speculation about thoracic breathing on this blog), but also blood hormone levels during practice, cat and mri scans during or after practice, etc. etc. etc.
one reason, perhaps, why yoga doesn’t look like cardio - the stronger and more confident i am in a posture, the *slower* my breathing and pulse are. maybe the challenge isn’t to bring your pulse up and keep it there for calorie burning and whatever, but to bring it down! - to maintain steady control and focus even in situations of extreme physical stress. which probably has measurable long-term health benefits of its own - but by a different mechanism than we’re used to on the treadmill. perhaps cardio might still be a good idea, at least to counteract the traditional yogic diet of sugar, milk, and ghee (someone should have told iyengar and guruji).
re: iyengar. advanced (or ‘intermediate’ in the specifically iyengar sense) practitioners of iyengar are serious, serious yogis. + i don’t really think sweating during practice has too much to do with jumping around or how hot it is (does anyone sweat as much doing typical cardio as they do in the primary series?) - but i find that sweat has a lot to do with my concentration. good iyengar instruction (even if it’s just warrior i, warrior ii, triangle, half moon, yawn) has me in a sweat almost instantly.
“You have to sweat 100%, not only physically but intellectually. If you sweat 100% intellectually then you know something of yoga. So 100% from the body ,100% from the intelligence. You have to sweat, intelligence has to sweat.” - Iyengar in Namarupa
Jim said,
July 21, 2006 at 2:10 pm
My observations are based on 40 years of fitness activities, with a strong emphasis on cardio activities such as marathon running and long distance cycling. For the last 2 1/2 years, I’ve done a mysore style ashtanga practice 4-5 times a week.
1. I think that comparing yoga to other fitness activities is not easy. You have to be clear about what type of yoga (especially given the difference between ashtanga and other practices in terms of exertion): ashtanga, Iyengar, bikram, etc. Also, the generally accepted benefits of yoga are not inherently quantifiable. (People subjectively report they’re calmer, they have better energy, or better concentration, results which are real but hard to measure.)
2. If the comparison is a narrow one between the cardiovascular fitness value of (a) an ashtanga yoga practice session and (b) a comparable number of minutes of other cardio training, I expect that a simple comparison of how many minutes the heart rate is in the target zone would tend to disfavor ashtanga. You’ll get your heart rate up faster and keep it in the target zone more easily if you go run, for example.
3. My admittedly subjective perception is that ashtanga has tremendous physiological (as opposed to psychological) benefits, however. When I’ve done a full primary series, I feel that I’ve had an intense workout. Comparing it to years of running and cycling, my brain says, “This is intense, hard work.” I think some of the physical intensity comes from doing the vinyasa’s fully, and that’s where a lot of the sweating originates. 75 minutes of a full primary series “feels” easily as hard as a 75 minute run or cycling activity (leaving aside race intensity or interval workouts).
4. Finally, the benefits of yoga are not purely cardiovascular fitness, as pointed out by many above.
5. I love long distance sports and the endorphin effect from sustained effort, but the overall systemic benefits of ashtanga feel richer and more longlasting. I doubt that this is measurable. So, if all you’re doing is counting heart rates in a target zone, ashtanga will have a “lower” value than other activities, but you may not be measuring the most important values.
Just one person’s observations.
Jim
susan said,
July 28, 2006 at 9:15 am
I love Jim.
Tracy said,
July 28, 2006 at 10:01 am
Hee hee.
Who IS Jim?
Odin said,
September 11, 2008 at 9:53 am
It’s frankly a ridiculous study and a waste of time and probably money too. Does anyone actually do yoga for its aerobic benefit?
It would be like measuring the 1 rep max strength of marathon runners - irrelevant beyond the scope of academic chin-stroking.
Physiologically ashtanga promotes relative strength, mobility and flexibility. If you are working through the primary series on a regular basis I’d also suggest you have admirable strength-endurance and work capacity. If you need more cardio for either health or sporting reasons then choose another mode of training and add it in to your week.
JMO
Marie said,
December 2, 2008 at 3:57 pm
From my personal experience I can say that my overall level of fitness improved drastically after participating in a regular yoga practice. I began with Power Yoga, then moved to Bikram. At first, I was not at all excited about Bikram. The heat was horrible. BUt I stuck with it because the studio was convenient (1/2 mile from my house) and they offered later class times (which was more suitable for my work schedule). In three months, I lost about 20 lbs, my eating patterns didn’t really change. The only significant difference in my diet was that my water consumption was higher. I was more flexible, stronger and had greater cardio vascular fitness. I felt those benefits much sooner than when doing “traditional” workouts of running, weight training etc. Just my two cents.