I am a yogi. I am also a skeptic. Sometimes, I wonder if they can co-exist. I cringe when an instructor says I am “wringing out the toxins” from my organs by twisting. Yet, eight years later, I still go back. I feel calmer and more in control of my body after yoga. This affects everything I do, from how I relate to others and how I eat and sleep to how I work and how I relate with them.
According to the most recent survey, more than 20 million Americans are practicing yoga. This makes it one of America’s most loved forms of exercise. Even Vladimir Putin, a fan of “macho sport,” has added downward dog to his list.
Is yoga really so good for your health? Is it able to improve our stress response or correct poor posture, as is often claimed? Perhaps our perceptions of yoga are biased. Perhaps there are some downsides to yoga, as some critics point out. The controversial New York Times story in 2012 reveals that yoga mats can cause serious injuries or even death.
I was looking for a more objective perspective on yoga’s health benefits, so I started to research science. I read more than 50 articles and spoke to seven of the most prominent yoga researchers around the world. I was shocked at the weak research in yoga almost immediately. Many studies were poorly designed and biased. Even worse, yoga comes in so many styles that it is difficult to determine how useful evidence can be for each style.
Based on all the research, I found that there are some things you can say about yoga. Despite what yoga haters say, it won’t harm you and is just as good for your overall health as similar exercise.
Yoga can also help reduce lower back pain and increase strength, flexibility, and inflammation, which in turn can help prevent chronic diseases and death. Recent research shows that yoga may increase body awareness. This refers to your ability to pay attention and feel the sensations inside of you. This is a big issue: Research suggests that a higher body awareness could improve people’s self-care.
However, another mind/body exercises, such as meditation and tai-chi, can also increase body awareness and decrease inflammation. This is the problem with much yoga research. It hasn’t revealed how yoga can be beneficial for certain health measures compared to other types of exercise. Many of the most outrageous claims about yoga, such as the claim that it can relieve constipation and wring out toxins from the body, are not supported by science or haven’t been thoroughly studied.
What is the current state of yoga science
In 1975, The Lancet published the first randomized trial (or high-quality experiment) on yoga. The trial showed yoga was more effective at lowering blood pressure than relaxation. However, the trial involved only 34 people, and they all had high blood pressure. It is therefore difficult to determine if the yoga effect would be replicated in a larger group of healthy individuals.
Although the number of yoga classes has increased dramatically, it is still plagued with the same issues as the early studies. Many yoga studies involve a small number of participants. Many studies lack a control group. Many people don’t want to compare yoga with other activities. For example, it would be nice to compare yoga against other forms of exercise or mind-body practices. This is not to compare, as one study found, whether yoga is better for back pain than giving people a manual on how to manage back pain.
FOR MOST CONDITIONS THE MAIN PROBLEM IS THAT WE DON’T HAVE ENOUGH EVIDENCE YET
Studies that do exist are usually short-term. Studies on mortality and serious diseases incidence are not long-term. Long-term studies of the possible harm yoga can cause to the body are lacking. Holger Cramer (director of yoga research at the University of Duisburg Essen in Essen), Germany says that “for most conditions”, “the main problem we don’t yet have enough evidence.”
It can be difficult to study yoga. Blinded research is generally considered to be the best type of research because the participants don’t know the exact intervention (such as a drug) and their biases or perceptions don’t affect the results. However, you cannot blind people to the fact they are doing yoga.
The biggest question in yoga research is: What defines yoga? Karen Sherman is a researcher with the Group Health Research Institute. She said that yoga can be many things to many people. “What you put into yoga interventions will impact what you get out.”
Yoga often involves a combination of postures and poses (asanas), controlled breathing (pranayama), meditation and relaxation (samyana). Many classes also include other elements such as chanting, heating and music. There are many variations in the teaching style and quality. Hatha and Iyengar yoga mainly consist of restorative and stretches, while vinyasa and ashtanga are more athletic and vigorous. Yin yoga won’t make you sweat, as you hold the postures for long periods of time for deep stretches. Bikram is 26 postures that are repeated twice in a heated room at 105 degrees. You can be certain you will sweat profusely.
Lorenzo Cohen is the chief of MD Anderson Cancer Center’s integrative medicine section. He told me that “many papers on yoga” don’t give enough detail about what they mean when they say “yoga”. How did yoga therapists get their training? What was their method of choosing different breathing techniques or postures?
A yoga class has so many components, it can be difficult to determine what is affecting your health. For example, did people feel more relaxed after attending a class? Did it have to do with the style of the teacher? It was the breathing exercises. Is it the heat? These factors can be difficult to quantify, so scientists might not be able to determine the exact benefits of yoga for people.
Nevertheless, yoga researchers that I spoke with said that the quality and quantity have been increasing, so we might get better answers in the near future. Cohen stated that there are more yoga therapy researchers. When smaller trials show benefits, it leads to better-designed trials. It is also possible to study yoga’s biological effects — how yoga classes affect hormone levels — to get a better understanding of the benefits yoga has on the body.