I have been to a couple of hot yoga classes and studios – and there is a wide variety of temperatures and humidity offered out there. I have also been to teacher training for styles that support heating a room, and with my background in exercise and fitness I am not convinced that extreme temperatures and humidity along with intense asana practice is necessary, especially for certain individuals.
Studios that I have been to that offer heated yoga have packed people in wall to wall, sweating over one another. When potential clients would ask me for power yoga classes(which I later found can be vastly different from hot yoga), I would direct them to a hot studio – the reply I received on numerous occasions was “I got a staph infection there”. Sure, lots of sweat, lots of people and carpeting just don’t mix. Enter MRSA. If you go, bring your own mat – too many people are not cleaning up their own bodily fluids and with cases of MRSA being reported – it never hurts to be safe.
I attended a teacher training in prenatal yoga with a pregnant “hot” yoga instructor – who worked in a room heated to 108 degrees. She argued that her body had grown accustomed to the heat and it was safe to teach during pregnancy. My argument, and the argument of several other experience instructors, was that the fetus’s body had not. There are reasons that hot tubs, steam rooms and saunas say “Not to be used by pregnant women” – denaturing happens from external stressors, such as heat.
Some studios claim fantastic health benefits from their practice. Weight loss, headache relief, back ache relief, and more. Questioning these claims can sometimes lead to a lengthy discussion on esoteric thought of yoga, purifying the mind/body – or sometimes the answer is a short “It does because our founder says so.” The idea that we are impure and somehow needed to be sweated into purity is one fraught with self-loathing disguised as a quest to become purified.
I took a friend of mine who had multiple medical concerns – thyroid cancer, gastro bypass weight loss, etc. When my friend became dizzy and ill during class, she was told to stay in the room to get the most benefit and not in a nice way. At this time my friend was only able to intake a restricted amount of fluids, mere sips, the teacher/studio was made aware of the conditions before class and invited her in saying the practice would be safe for her. I suggested she leave and cool off, I left after grabbing my mat and have never been back. Please keep in mind that these teachers are not medical professionals, no yoga teacher (myself top at the list) is licensed to give out medical information or make judgments/recommendations about medical conditions as a professional. A great deal of yoga teachers have no more than a weekend’s worth of training to teach, and no training in exercise physiology (apologies to those of us out there who do).
My last bit of information to share is taken from my profession as a personal trainer/ group fitness instructor.
Here is a chart used in the safety section of every certification book I can think of, books that are written by MDs, PhDs, and other health/fitness professionals who have to answer to state and professional regulatory boards. This chart colorfully explains the risk of exercise (beyond lets say walking to the car, walking the dog, etc.) in heat/humidity conditions. Look at this chart and be informed before you make your choices: