There are, of course, many forms of yoga, from those that focus on breathing and feature mostly sitting postures to those that entail holding complex standing poses and moving quickly through a series of poses. Larson-Meyer’s survey found that there’s equally great variety in these sessions’ intensity. Most were found to have a score of 2 to 3 on what’s known as metabolic equivalent of task (MET), a system used to compare energy expended in various activities. A MET score of 1 is considered the baseline, and corresponds to sitting or otherwise being sedentary. A MET score of 3 means an activity has roughly the same energy expenditure as walking at a leisurely pace. Activities with a MET score of 2 to 3 are considered light activity.
A key exception was surya namaskar, or sun salutation (seen in the video below). This is a series of standing, lunging and other poses, done relatively quickly and usually repeated two to six times. Depending on how vigorously they’re done, sun salutations typically produce a MET score of 3 to 6, which is considered moderate activity. (By way of comparison, running at 9:00-per-mile pace has a MET score of 10.5, well into what’s considered vigorous activity). In one study Larson-Meyer reviewed, sun salutations were done vigorously enough to produce a MET score of 7.4, the equivalent of a walk-run combination averaging between 12:00 and 15:00 per mile.
Larson-Meyer’s findings support the conventional view that yoga isn’t a huge calorie burner. Given the MET scores Larson-Meyer found, a typical half-hour session might burn around 150 calories, or roughly the amount you would expend in walking a mile and a half in that time. In a practical sense, even more intense routines, such as a vigorous sun salutation, won’t match running for weight loss, given that you’re unlikely to do such a series of poses uninterrupted for an hour.
As for “hot yoga,” Larson-Meyer wrote, “Despite purported claims that a Bikram yoga session expends up to 1,000 [calories] in 90 minutes, the MET values of Bikram yoga, performed in hot room with 40% relative humidity, were within the same range as yoga practiced at room temperature.” In a hot classroom, your heart rate will be higher and your sweat losses greater because of the temperature, but your long-term caloric burn will still be relatively low.
Rebecca Pacheco, who guides the Runner’s World yoga videos and is the author of Do Your Om Thing, noted that the studies Larson-Meyer reviewed mostly looked at Hatha and Bikram yoga sequences. “There are so many different styles of yoga today, many of which are highly physical and blended with other forms of fitness,” Pacheco said. “The articles referenced for the study date back as far as 1965—before the advent of two of the most popular and vigorous styles, Power Yoga and Vinyasa Yoga.”
Yoga for Runners
Pacheco urged runners to think about vigorous yoga beyond its MET score or caloric burn.
“Sun salutations are an efficient, well-rounded, accessible movement that warms up the body in a highly effective way,” she said. “In addition to its aerobic benefit, this signature yoga sequence features forward bending, backward bending, upper and lower body strength, as well as core power. The whole body is worked in concert. For this reason and others, sun salutations are great for runners.”
At the same time, Pacheco said that even a more vigorous form of yoga might not provide enough of an aerobic workout to fully substitute for running when you’re hurt.
“Yoga can be a helpful form of cross-training and way to maintain fitness while injured, and certain styles are definitely great workouts,” she said. “Sun salutations or classes built upon them (i.e., Vinyasa or Power Yoga) are ideal for this. However, as someone who’s run two Boston Marathons and been a lifelong runner and yogi, I wouldn’t recommend yoga as a carte blanche substitute. The elliptical, bike, or pools are also key ways to stay in running shape when actual running is prohibited.”
Pacheco said that, as in running, consistency is key with yoga.
“I recommend scheduling one class per week at your local studio or doing at least one of my long videos online at the Runner’s World Yoga Center. Another great approach is the shorter videos we created throughout the week, perhaps after a run or on an cross-training day.”
Also similar to running, when to do yoga, and in what form, varies depending on the totality of your training.
“The goal of yoga for runners is to make running more efficient, powerful, and enjoyable,” Pacheco said. “Yoga the day after a long run is a must in our house. It’s the perfect recovery activity or dose of ‘active rest.’ The blood flow to tired muscles is essential after a long run, in particular. Yoga feels equally great after a track workout or on a non-running day. The key is to consider what your body is preparing to do the next time out. Vigorous yoga is great for cross-training, for example, but you may want something milder after a long run and definitely before a big race.
As a general rule, I encourage runners to do the yoga they enjoy,” she said. “If our bodies are feeling tired or beat up, if a runner is extremely tight or injured, then a more gentle or static yoga practice is preferable. If a healthy runner wants a more challenging practice with aerobic and cross-training benefits, then sun salutations are a great place to start. The Vinyasa practice is largely built upon these movements and is the most popular style practiced in the U.S. today.”