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

Who IS Jim?

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

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

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/).

Word.