The science of yoga – is it true what they say?

I am exhausted and shaking and just want to lie down on my back, close my eyes and let soothing music roll over me like a warm soft wave. Completely ignoring my telepathic transfer of the word Shavasana (resting pose), my teacher tells us to stand on our heads. I fight the urge to just collapse and sneak a preview to Shavasana, and seek refuge in my teachers calming voice. He starts explaining how standing on my head stimulates my thyroid gland, which is crucial to strengthening my immune system. My fatigue quickly dissipates as my head takes on new and darker shade of red, matching the irritation rising inside me. A quick internal scan of my anatomy knowledge tells me that the thyroid gland controls our metabolism and is not really that involved in the immune system. What is he talking about? A few uncomfortable moments later, I realize that he probably meant to say thymus; a specialized organ of the immune system. Harmless mistake, you might argue, but if he doesn’t know the difference between a thyroid gland and a thymus organ, what does that say about his claim regarding strengthening my immune system? On top of that, I am not really convinced that I want my immune system to be stronger than it already is, but that’s a different blog post. I come out of my headstand and lie down on my back, ready for Shavasana. I close my eyes but can no longer find peace and the music is more irritating than soothing. What happened to the zen I was feeling a minute ago?


After my yoga class, I went home and checked the scientific literature for studies showing a connection between inverting your body and the thymus, but couldn’t find a single one. Surprise! He made it up, or picked it up from someone else who made it up, or picked it up from someone else who made it up. You get my point.
As a scientist and a person who practices yoga on a regular basis, I often find these two passions of mine conflicting, and I have been close to giving up yoga on multiple occasions because of bogus claims made by my teachers, ripping my out of my zen and infuriating me. Why can’t I just ignore these harmless claims? Why do I let it get to me? One could argue that there is no harm done, as there are very few risks associated with yoga. But I beg to differ. Whenever false scientific claims are made, they are picked up and repeated and they grow and they turn into myths that are really hard to get rid of and can be potentially harmful.I’ll give you an example. I was in a yoga workshop focusing on anatomy, hoping to understand where some of the many physiological claims I heard in class were coming from. Among a lot of other BS, our teacher claimed that our fascia (a thin sheath of fibrous tissue enclosing a muscle or other organ) slowly dries out like a dry sponge in a kitchen. Once dry, it is very hard to get it wet again, just like the dried-up kitchen sponge. Therefore, if we were experiencing difficulties in absorbing the water we drink, it might be because of our dry fascia (Because it’s not normal to pee out excess water???). A girl in class held up her hand, looking very concerned. She drank over five liters of water (yes 5!) every day, but still felt thirsty, she explained. The teacher asked if she had trouble holding her pee for more than an hour, to which she answered yes (no wonder, if your drinking like fish all day!). She was told that she might have dry fascia and should practice more yoga and maybe take some herbal supplements. I exploded in a “you should go to the doctor and get checked for diabetes,” but my comment was largely disregarded. I don’t know what happened to the girl, but I do think that this is one of those times where false scientific claims that seem harmless at first, can turn into life-threatening situations.I love yoga. It works wonders for me, mentally and physically. There is absolutely no need to lie when it comes to the benefits of yoga. Some are very obvious, like increased flexibility, peace of mind, reduced stress, and many have actually been proven in scientific trials. Going through the scientific literature on yoga is a big undertaking, and the studies wary greatly in design and credibility. I chose to focus on the meta-analyses, a statistical method that combines the results from many studies, usually making the conclusions stronger and more tenable. In the picture above are some of the proven benefits of yoga, tested in multiple studies and found to be true, or – in the case of relieving schizophrenia symptoms – not to be true.
I feel great after yoga, and I have no doubt it is good for me, but I wish my teachers would stop making false claims about the advantages of yoga. Or at the very least, mention that their claims are founded in personal belief and have not been solidified or proven in any way.