RELATED: How Much Exercise Is Enough to Reach My Health and Fitness Goals? There are a variety of yoga styles — vinyasa, restorative, hatha, and hot, just to name a few. Each requires a different amount of physical exertion. There’s a big difference between a restorative yoga class with very little movement and a fast-paced vinyasa class where you’re quickly moving from one challenging pose to the next. The latter may require enough exertion, and elevate your heart rate enough, to qualify as moderate physical activity; the former may not, explains Edward Laskowski, MD, a physical medicine and rehabilitation specialist and the former co-director of the Mayo Clinic Sports Medicine in Rochester, Minnesota. “Classes that focus more on mindfulness and restoration may not get your heart rate up that much,” says Dr. Laskowski. Some classes are geared toward getting people to a higher heart zone rate where you’re challenging and working the heart much more, which may indeed be an aerobic workout, he says. Here’s what you should know about yoga and your fitness. RELATED: Everything You Need to Know About Strength Training (and Why It’s So Good for Us) One study found that, at the end of the study, women who did an hour of ashtanga yoga twice a week for eight months were able to lift more weight with their legs compared with women who didn’t do yoga. (2) Another study found that yoga improves core and upper body strength and endurance; participants were able to do more curl-ups and push-ups after six weeks of classes. (3) But the muscles you build in a yoga class may differ in some ways from the muscles and muscle tone you build from other types of strength training, Laskowski explains. Yoga is more about functional strength, he says. In weight training, for example, you might isolate a certain muscle (like the biceps) to strengthen it. In yoga, on the other hand, you use muscle groups together. “We use a bunch of different joints and muscles in yoga, which is nice because that’s what we do in our daily life,” he says. For example, the average 20-year-old’s heart should be beating between 100 and 170 times per minute to be in the moderate to vigorous activity range, whereas a 60-year-old’s heart rate should be beating between 80 and 136 times per minute to be in that range. Yoga is not necessarily an aerobic exercise in the same category as walking, running, biking, or using an elliptical machine, says Laskowski. Whether or not a yoga class will get your heart rate in the targeted zone to count as moderate physical activity depends on the type of yoga and how intensely you’re moving through it, says Laskowski. Classes that focus more on mindfulness and restoration may not get your heart rate up as much as more athletic classes that are designed to keep you moving, he adds. A study that looked at heart rate in ashtanga, hatha, and gentle yoga found only a modest elevation of heart rate. Participants in ashtanga, the more active type of flow yoga, had an increase of about 30 beats per minute, whereas hatha and gentle yoga students had an increase of only about 15 beats per minute. (5) Depending on your age and resting heart rate, that amount of activity might be enough to count as moderate exercise, but for others it would not. That doesn’t mean it’s not worthwhile, says Laskowski. It’s still activity, after all — it’s just less intense than something that gets your heart rate up more (just as jogging is less intense than running). “The heart is a muscle, and when you challenge it by elevating heart rate you cause it to adapt and get stronger, so anything that does that is helpful,” he says. “The guideline is between 200 and 600 calories [burned] per hour, which is a big window, because there are so many different forms of yoga,” she says. In a restorative yoga class, you’re relaxing deeply and likely not going to burn many extra calories. But you will burn a lot more calories in a vigorous class where you’re moving a lot, Sherwin adds. According to calorie estimates calculated at Harvard Medical School, the average 125-pound person burns about 120 calories in a half hour of hatha yoga, and a 185-pound person burns about 178 calories in that half hour. Hatha yoga is a general category that includes vinyasa or flow yoga. (6) In comparison, a 125-pound person is estimated to burn 135 calories in 30 minutes of walking (at a pace of 15-minute miles) and 210 calories bicycling at a moderate pace on a stationary bike. (6) Although you might sweat a lot more in Bikram yoga, the calorie tally is roughly the same. In a study by a team of researchers from Colorado State University (presented at the national conference of the American College of Sports Medicine) found that in a standard 90-minute class that goes through 26 poses in a room heated to 105 degrees and 40 percent humidity, women burned an average of 330 calories and men averaged about 460 calories, which isn’t too far from the calories burned walking briskly for the same amount of time. (7) There is evidence that practicing yoga can help with weight loss potentially indirectly through the lifestyle changes it encourages. In a study performed at the National Institutes of Health Clinical Center (published in the journal Evidence-Based Complementary Alternative Medicine), people who practiced Iyengar yoga (a slow-moving type of yoga that focuses on body alignment and posture) and lost weight after taking up the practice, were interviewed. (8) The researchers identified several factors (based on the interviews) that may have contributed to the Iyengar yogis’ weight loss: a shift toward healthy eating, feeling supported by a culture that promoted healthy eating and behaviors, and physical changes like muscle building and toning.
