Hot Yoga "TEA"
Hot Yoga is a type of yoga practiced in heated rooms. Heat has a long history of being part of healing practices, and yoga is now recognized as a potential preventative strategy for physical and mental ailments. The combination of both heat and yoga creates an environment where the body and mind can beautifully unfold and sync together.
"TEA" : Theory + Evidence + Action
Originally, a practice called panchagni tapas involved doing yoga surrounded by a ring of flames in the midday sun in India. Panchgni tapas was part of a common ritual of fire sacrifice, called asagni hotra in Sanskrit. It was believed to increase the power of your will. Now it is not advised, due to the potential harm of overheating the body.
Later hot yoga developed in response to an intrigue for the sauna. Bikram Choudhury's yoga students in Japan in the 1970's would take saunas at lunch, and he was curious about the health benefits. He heated his class first to 28 degrees Celsius to match his home town of Calcutta, India. He then increased the heat to 40 degrees, which is the temperature used in many hot yoga studios today.
Heat has been used for centuries to transform the body mind and soul.
Finland has built-in saunas in most households, since the Middle Ages or even earlier, more than 2000 years ago. Named savusaunas - a similar sound to savasana incidentally - the Finnish saunas were smoke heated. When the metal woodstove was designed, temperatures in Finnish saunas reached 75 to 110 degrees Celsius.
In Finland, the sauna was first considered a holy place. An altar to the gift of fire from the gods, a Finnish saying refers to holding an attitude of respect when in the sauna - saunassa ollaan kuin kirkossa. Some believed there was a sauna gnome or elf. Later, Finns considered the sauna a place of refreshment, as in to refresh the body and mind.
Also located in the Baltics and Scandinavian countries, and revealed in archaeological digs in Greenland and Newfoundland, the sauna culture spread from Nordic lands to European countries after the world wars.
First mentioned in the 15th Century, the Korean sauna called a hanjeungmak was used to cure illness.
The Turkish hot steam baths evolved to reach 40 degrees Celsius, as the wet heat would otherwise scald the skin.
The North America's are known more for their sweat lodges or the Mexican sauna called a temazcal. These were used for therapeutic sweating or ritual - for physical, mental, and spiritual healing, for purification.
The Japanese bathing culture, which includes the sauna, is traced back to Buddhist temples in India. From India, the bathing practices travelled to China then Japan in ~ 700 AD. Originally steam baths based in heated pools or hot springs, the sauna room was added much later, likely around the 1970s, when the bath houses expanded their designs.
T : Theory
The benefits of prolonged sweating are believed to be detoxification, illness prevention, better skin health, increased physical perseverence, and improved physical focus. Ancient traditions from around the world also believe that a spiritual purification occurs.
E : Evidence
When you sweat, you rid the body of toxins. Studies show that many toxic elements are preferentially excreted through sweat (1,2,3,4). Bisphenol A and phthalates, chemical compounds linked to disease (phthalates are endocrine disruptors), was found to be released in sweat even when it was not detected in blood or urine testing. The study of sweat analysis and applications for health is part of "metabolomics" which is a filed that informs the new more molecular field of Precision Medicine (6).
Sweat also carries common body chemicals out of the body: salt, amino acids, decarboxylic acids, and metabolites like uric acid, tyramine, inosine, choline (8).
How do you replenish losses from sweat?
Studies on sweat losses in humans are limited (9). However, small studies show that exercise-induced sweat leads to losses of salt, potassium, calcium, magnesium, copper, iron, zinc, and iodine (10,11,12). Interestingly, the body acclimatizes to heated exercise after 10 days and then losses of these minerals are less - this study was done in 45 degrees Celsius and 20% humidity (10).
Ratios of minerals lost have been estimated. For the study on 7 hours of continuous sweating in 25 or 25 degrees Celsius. There was no difference to percentage lost of minerals with the two different heated conditions. The ratios were magnesium 12 : salt 8 : potassium 2 : copper 0.8 : calcium 0.1 - these amounts are in 100 ng/mL, ie. 12 is 1200 ng/mL (11).
Although studies have not concluded that athletes need to supplement with nutrients or trace minerals, there are advantages to adequate trace mineral presence in the body. For example, magnesium increases muscle use of sugar and clearance of lactic acid (13).
Natural antibiotics are found in the skin, and one of these, called dermcidin, is released when we sweat (14,15). Lymph fluid flow increases during hot yoga; lymph carries away elements that would otherwise prevent body repair and immune system function.
Muscle and Fascia Release
In the hot yoga environment, due to both the heat and the humidity, the muscles and fascial layers are able to stretch more. For an analogy, consider plastic that is heated. It becomes more mobile. As a result, you need to pay attention to your poses and stretches in hot yoga, so as to not overstretch, leading to tears and then stiffness. However, if you can stretch to where you have sensation, and not pain, then the heat can assist in a releasing of tight areas in muscles or fascial layers.
Muscles strengthen with hyperthermic conditioning. Dr. Rhonda Patrick has studied how the body optimizes when heat is a part of regular exercise:
- improved cardiovascular mechanisms and lower heart rate (16)
- lower core body temperature during workload
- higher sweat rate & sweat sensitivity with better temperature control (17)
- increased blood flow to skeletal muscle and tissues (17)
- reduced rate of glycogen depletion due to improved muscle perfusion (18)
- increased red blood cell count (19)
- increased efficiency of oxygen transport to muscles (19)
Heat exhaustion, heat stroke, and dehydration are some of the risks of a hot yoga practice. In addition, certain chronic illnesses or physical vulnerabilities are not suited to a hot yoga practice such as heart disease or a sweat gland disorder. In addition, women in their second or third trimester of pregnancy should not practice hot yoga. Consult your family doctor before taking hot yoga if you have a medical condition.
Otherwise, ensure to hydrate before and after, include salt in your diet, and consider an electrolyte hydrator or trace mineral supplement. Trace minerals exist in whole foods such as lemons, watermelon, cucumber, so you can add these to water to increase nourishment to your system. If you feel dizzy or lightheaded or nauseated during a class, lie down on the mat and your teacher will come over and assess how you are. Do not leave the class without first talking to the teacher, as you could faint and this could lead to a more serious injury such as a head injury.
Hot yoga studios exist all around the world. Styles range from structured to not structured, a pre-set series of poses, vinyasa or power hot yoga. Studios range in degree temperature and humidity. Some studios offer infrared heating. Some offer more of an athletic approach, others a more meditative and positive psychology approach.
Once you are confident that you can practice hot yoga with no adverse health effects, simply try different studios until you find a studio and a teacher that works best for you. Try it in the morning versus the evening, and notice if you have a preference. Be sure to hydrate adequately and nourish the body responsibly with nutrients and minerals. Do not eat 2 to 3 hours before practice. Drink minimally prior to practice so that the stomach is not full. Notice if, after 6 weeks of practice, you feel better or worse, if you skin health has changed, if your energy is increased. Find what works best for you.
In summary, there are advantages and disadvantage to a hot yoga practice.
- skin health
- release of toxins and enhanced body detoxification mechanisms
- improved muscular endurance
- improved flexibility if practicing with appropriate stretching
Potential advantages include:
- increased focus and determination
- more positive mental approach if classes enhance a positive mindset
- a spiritual practice if your belief systems align with ancient hot practices
- loss of nutrients, trace minerals, dehydration
- heat exhaustion, heat stroke, exacerbation of illness
Each individual will have a preference, linked to current physical composition, genetic vulnerabilities, personality, and belief system. Find what works best for you by identifying your goals, and then seeing if your desired outcome is reached.
A personal note:
I was inspired for this blog post after our YHOT hot yoga teacher training. A practice developed by Alex Atherton and Kristin Campbell, the yhot practice is a set series or poses with room for creative variation. Practiced in heated and humid rooms, it is a gorgeous opportunity to focus the mind and transform the body. There is an indescribable shift in state, where you feel cleansed, clarified, and renewed. The determination required to move through the practice, fuels a fire that applies to your life off the yoga mat.
As a physician, I am responsible to present my thoughts in the world, in a way that is in accordance with the standards and guidelines of my profession. So, I naturally became curious about the science and "medicine" of hot yoga. There is much more to say than these words below, but for a short blog post, these are some relevant areas I thought to mention.
I am also writing in part as, I am so excited and honoured to have started a teacher training mentorship with the potent and inspiring Hillary Keegan at YYoga, and so pleased to be developing the practice of YHOT that my friend Alex Atherton refined with Kristin. It's such a beautiful practice that has benefits for me, and I am curious as to how it may have benefits for other busy professionals out there, or those seeking mental clarity combined with athletic toning.
~ Dr. M.
1. Genuis et al. 2011. "Blood, urine, and sweat (BUS) study: monitoring and elimination of bioaccumulated toxic elements." In: Arch Environ Contam Toxicol. University of Alberta, Canada.
2. Genuis et al. 2012. "Human excretion of bisphenol A: blood, urine, and sweat (BUS) study." In: J Environ Public Health. University of Alberta, Canada.
3. Genuis et al. 2012. "Human elimination of phthalate compounds: blood, urine, and sweat (BUS) study." In: Scientific World Journal. University of Alberta, Canada.
4. Hussain et al. 2017. "Working Up a Good Sweat - The Challenges of Standardizing Sweat Collection for Metabolomics Analysis." In: Clin Biochem Rev. RIMT University, Australia.
5. Kahn MD 2014. "Why Sweating Is The Best Way To Get Rid Of Toxins." In popular literature Mind Body Green.
6. Beger et al. 2016. "Metabolomics enables precision medicine: "A White Paper, Community Perspective". In: Metabolomics. International multi-country group of authours from various universities and biochemistry departments.
7. Mena-Bravo and de Castro. 2016. "Sweat: a sample with limited present applications and promising future in metabolomics." In: J Pharm Biomed Analysis. University of Cordoba, Spain.
8. Calderon-Santiago et al. "Optimization study for metabolomics analysis of human sweat by liquid chromatography-tandem mass spectrometry in high resolution mode." In: J Chromatogr A. University of Cordoba, Spain.
9. Baker 2017. "Sweating Rate and Sweat Sodium Concentration in Athletes: A Review of Methodology and Intra/Interindividual Variability." In: Sports Med. Gatorade Sports Science Institute, Illinois, USA.
10. Chinevere et al. 2008. "Effect of heat acclimation on sweat minerals." In: Med Sci Sports Exercise. US Army Research of Environmental Medicine, USA.
11. Montain et al. 2007. "Sweat mineral-element responses during 7 h of exercise-heat stress." In: Int J Sport Nutr Exerc Metab. US Army Research Institute of Environmental Medicine, USA.
12. Smyth and Duntas 2005. "Iodine uptake and loss-can frequent strenuous exercise induce iodine deficiency?" In: Hormone Metab Res. University College Dublin, Ireland
13. Chen et al. 2014. "Magnesium enhances exercise performance via increasing glucose availability in the blood, muscle, and brain during exercise." In: PLoS One. Multiple hospitals and universities, Taiwan.
14. Barak et al 2005. "Antimicrobial peptides: effectors of innate immunity in the skin." In: Adv Derm. University of Pennsylvania School of Medicine, USA.
15. Schitteck. 2012. "The multiple facets of dermcidin in cell survival and host defense." In: J Innate Immune. University of Tübingen, Germany.
16. Hannuksela, M. L. & Ellahham, S. Benefits and risks of sauna bathing. The American journal of medicine.
17. Costa et al 2011. Heat acclimation responses of an ultra-endurance running group preparing for hot desert-based competition. In: European Journal of Sport Science. Coventry University, UK.
18. Costill et al. 1985. "Muscle metabolism during exercise in the heat in unacclimatized and acclimatized humans." In: J Appl Physiol.
19. Scoon at al 2007. "Effect of post-exercise sauna bathing on the endurance performance of competitive male runners." In: Journal of science and medicine in sport / Sports Medicine Australia. University of Otago, New Zealand.