Yoga styles differ in their physical intensity
Research Study At A Glance
The Research Question Asked
Does physiological intensity of yoga differ between styles?
Type of Study
Review study
Methods
The authors conducted a review of previously published research. They used the PubMed database to identify studies which evaluated practitioners of a specific yoga style or styles for heart rate, oxygen consumption (amount of oxygen used by tissues in the body over a defined period of time), or metabolic equivalent of one or both of those. They included the following yoga styles, evaluated in one or more of the smaller studies, in the review: Ashtanga, Bikram, gentle, hatha, Iyengar, power, and vinyasa. Ten papers met the criteria for the review study. Those papers were published between 2005-2018, and included 222 total participants who ranged in age from 18 to 67.
Results
Hatha, Ashtanga, and Bikram styles of yoga were categorized as light intensity based on oxygen consumption, while vinyasa yoga was categorized as moderate intensity. Oxygen consumption was not measured for the other styles of yoga evaluated in the review.
Based on heart rate, Ashtanga and gentle yoga were categorized as light intensity, power and vinyasa were categorized as moderate, and Bikram was categorized as vigorous. Hatha and Iyengar styles of yoga were more variable. They were categorized as light/moderate and light/vigorous, respectively.
Conclusion
There are large variations in intensity between styles of yoga based on oxygen consumption and heart rate. Variation in intensity between yoga styles was due to the variability of what practitioners were doing over the whole arc of a yoga practice. Yoga practice could range from higher intensity sun salutations to lower intensity seated postures. A heated practice room, such as that in Bikram, and length of holding postures also contributed to differences in intensity ratings.
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Background
As interest in yoga has spread in the West, methods of practice have expanded to include modifications and spin-offs of more traditional styles. Researchers in western medicine have also become more interested in yoga’s potential contributions to a variety of diseases and dysfunctions in the body. Studying the effects of yoga practice, particularly comparing yoga to other treatments in clinical studies, is difficult because what is meant by “yoga” varies considerably.
Many different styles of practice have made it to the West at this point. One way to more objectively compare the effects of styles of yoga is through measurement of physiological responses, like heart rate or metabolic response, across a whole session of a particular style of yoga. In this review paper, the authors have identified previously published individual studies where the researchers examined one or more of those physiologic responses for a particular style of yoga in order to compare the effects and intensity of one style to another.
Research question
Does physiological intensity of yoga differ between styles?
Research methods
The study authors conducted a review of previously published research using the guidelines from Preferred Reporting Items for Systemic Reviews and Meta-Analyses (PRISMA). They conducted the review of the literature using the PubMed database and included only studies published in English. They used the following keyword search terms: yoga, intensity, heart rate, oxygen consumption, and energy expenditure.
The researchers evaluated published research studies for relevance to their review study by using a modified version of the American Dietetic Association Quality Criteria Checklist. The checklist includes four questions on “article relevance” and ten questions on “article validity”. These scores were used to determine the strength of the research study. The researchers included studies in their review that rated as either positive or neutral, with respect to relevance and validity. They identified ten papers, published between 2005-2018, that met the criteria and included those in the review study.
All included studies evaluated the heart rate, oxygen consumption (amount of oxygen used by tissues in the body over a defined period of time), or metabolic equivalent of one or both of those, for practitioners of a specific yoga style or styles. The authors used physiologic measures to categorize the yoga styles as light, moderate, or vigorous intensity. Yoga styles evaluated in one or more of the smaller studies included: Ashtanga, Bikram, gentle, hatha, Iyengar, power, and vinyasa. All smaller studies included in the review evaluated a full session of the style. There were 222 total participants included in all of the smaller studies combined and they ranged in age from 18 to 67.
Results
Intensity of yoga styles based on oxygen consumption:
- Hatha = light
- Ashtanga = light
- Bikram = light
- Vinyasa = moderate
(Oxygen consumption was not measured for the other styles of yoga evaluated in the review.)
Intensity of yoga styles based on heart rate:
- Ashtanga = light
- Bikram = vigorous
- Gentle = light
- Hatha = light/moderate
- Iyengar = light/vigorous
- Power = moderate
- Vinyasa = moderate
Generally, there were large variations in intensity between styles of yoga based on oxygen consumption and heart rate. Not all yoga styles received the same intensity classification rating for oxygen consumption and heart rate.
Some of the variation in intensity between yoga styles was due to the variability of what practitioners do over the arc of an entire yoga practice. That might include sun salutations, which are higher intensity than other parts of practice. And it could also include seated postures, which are lower in intensity than other types of yoga postures. Heated practice such as that in Bikram can also influence intensity ratings in the form of oxygen consumption and heart rate. Length of holding postures can result in a discrepancy of intensity ratings. This is because long holds can increase heart rate without necessarily increasing oxygen consumption.
Why is this relevant to yoga practitioners?
Students seek out a yoga class or practice for many different reasons. Additionally, what we mean by yoga varies considerably from one practice style to another. For these reasons it can be helpful to identify some objective measures to describe individual yoga styles. This can help new practitioners make more informed choices about what yoga styles to begin with when they are starting out, based on what their intentions are with respect to starting a yoga practice.
Additionally, researchers in western medicine have been increasing their exploration of yoga as a treatment for many disorders and diseases. When we compare yoga to other treatments for disease in a clinical setting, it’s clearer if we describe the effects of the yoga using more objective measures. This review paper provides practitioners and researchers with more information about the ways that styles of yoga are similar and different. This helps everyone stay more informed as they engage with the practice of yoga.
Conclusion
Yoga is a versatile, variable tool that can have impacts on many different aspects of our well-being. We may seek out a yoga practice for many different reasons. So, it’s helpful to have a clearer picture of what individual styles of yoga offer. This review paper provides information about the physiological impacts of common styles of yoga practice. That can help us make choices about which style might be a good fit for us.