Hot yoga has become one of the most recognisable forms of modern yoga practice. Heated studios are often associated with deeper stretches, detoxification, and heightened intensity.
I taught hot yoga in London for several years and genuinely enjoyed the experience. One thing I noticed is that heated classes often attract people who might never otherwise try yoga. For many students, hot yoga becomes an accessible entry point into the practice, and that is a positive thing.
But alongside the popularity of hot yoga, several claims have taken root in yoga culture. Some are partially true. Others are misunderstandings of basic physiology.
In this article, we will explore a few common hot yoga myths and look at what current science suggests.
Some of the material below is adapted from my book The Physiology of Yoga.
Myth 1: Heat Makes People Too Flexible and More Likely to Get Injured
A common claim is that heated environments make tissues overly flexible, increasing the likelihood of injury.
The physiology is more nuanced.
Higher tissue temperatures are associated with reduced passive stiffness and increased stretch tolerance. In other words, people may feel able to move further when their bodies are warm.
However, this does not automatically mean that tissues have structurally lengthened or become unstable.
Most improvements in flexibility during stretching are believed to come from increased stretch tolerance rather than permanent changes in connective tissue length.
Stretch tolerance refers to the nervous system’s willingness to allow a joint to move further before producing the sensation of discomfort or stretch. Over time, the brain becomes more comfortable with that sensation, allowing a person to access greater range of motion without necessarily changing the structure of the tissues themselves.
In fact, warm muscles and tendons generally tolerate strain better than cold tissues. This is why athletes warm up before sprinting or lifting.
Injury risk in yoga is more likely influenced by factors such as:
• excessive loading at end range
• fatigue
• competitive environments
• lack of strength or control in extreme ranges of motion
• individual factors such as hypermobility
Temperature alone does not determine whether a practice is safe or unsafe.
Interestingly, there is very little research that specifically examines injury rates in hot yoga classes. Most studies look at yoga practice in general rather than heated environments. However, many teachers who have worked in heated studios for years report very low rates of acute injury among students.
Context, cueing, and class culture likely matter far more than the thermostat setting.
Myth 2: Sweating Means You Are Releasing Toxins
“Yoga for detox” is a very popular theme in the yoga world, especially in hot yoga environments. But is sweating actually helping us detoxify?
To answer that, it helps to understand how detoxification works.
Our bodies are regularly exposed to toxins, which are poisonous substances produced by living organisms. These include substances produced within the body itself, such as lactic acid and microbial waste products in the gut.
The body removes these substances primarily through the liver, faeces, and urine.
The physiological processes through which the body identifies, neutralizes, and eliminates toxic substances and metabolic byproducts are known collectively as detoxification.
The liver plays a central role by chemically altering potentially harmful substances so that they can be safely excreted.
Without this detoxification system, we would quickly become very unwell.
Sweat glands are often thought to perform a similar excretory role to the kidneys. However, evidence suggests their role in removing toxins is relatively small.
In a comprehensive review, Baker (2019) concluded that the role of sweat glands in eliminating waste products and toxicants from the body appears to be minor compared with other pathways of breakdown and excretion.
That said, sweating still serves important functions.
Studies suggest perspiration contributes to skin hydration and microbial defense (Schröder and Harder 2006; Watabe et al. 2013).
So, while heavy sweating in a hot yoga class may feel cleansing, it is unlikely to meaningfully remove toxins from the body.
Myth 3: Hot Yoga Burns Dramatically More Calories
Another common claim is that hot yoga dramatically increases calorie burn.
The logic seems straightforward. If you are sweating more and your heart rate is higher, you must be burning significantly more calories.
However, sweating itself does not indicate greater energy expenditure. Sweating is primarily the body’s cooling mechanism. It reflects thermoregulation rather than calorie burn.
Research suggests that the number of calories burned during yoga depends far more on the type and intensity of the movement than on room temperature.
More vigorous styles of yoga may increase heart rate and metabolic demand, but simply raising the temperature of the room does not automatically produce a large increase in calorie expenditure.
That said, many people do practice yoga in part to burn calories, and there is nothing inherently wrong with that motivation.
Yoga can support strength, mobility, cardiovascular health, and energy expenditure. For some students, the calorie-burning aspect of movement is an important part of why they choose to practice.
Who are we to judge?
Movement is beneficial for many reasons, and if practicing yoga helps someone move their body more regularly, that is likely a positive outcome regardless of their initial motivation.
What About Detox Diets or Detox Programs?
The idea that a particular pose, diet, or product can remove toxins from the body is very appealing. However, scientific evidence supporting detox programs is extremely limited.
In a review examining studies on detox diets, Klein and Kiat (2015) concluded that there is very little clinical evidence supporting the use of detox diets, despite a booming detox industry.
They noted that no randomized controlled trials have been conducted to properly evaluate commercial detox programs in humans.
Some chemicals, such as persistent organic pollutants, phthalates, bisphenol A, and certain heavy metals, can accumulate in the body and may take years to be removed. These substances are linked to various chronic diseases.
However, there is no evidence that a specific yoga pose, detox diet, or product can rapidly eliminate them.
Does Yoga Support Detoxification at All?
Possibly, but not in the way it is often described.
Exercise, including yoga, appears to support overall physiological health in ways that may indirectly help the body's natural detoxification systems.
One of the most powerful effects of exercise is its anti-inflammatory impact.
Chronic inflammation is associated with many diseases, including cardiovascular disease, diabetes, cancer, obesity, osteoporosis, and Alzheimer’s disease (Tabas and Glass 2013).
Exercise has been shown to reduce inflammatory markers and create an anti-inflammatory response in the body (Flynn, McFarlin, and Markofski 2007).
Another well-known effect of exercise is improved circulation. Greater blood flow helps deliver oxygen and nutrients throughout the body and supports organs involved in detoxification.
In these ways, movement may help optimize the body's existing detoxification processes rather than acting as a direct detox method itself.
The Takeaway for Yoga Teachers
Hot yoga is often surrounded by bold claims.
Current evidence suggests:
• Heat may increase short-term range of motion and stretch tolerance.
• Sweating is not a major pathway for detoxification.
• Calorie expenditure depends more on movement intensity than temperature.
• The body already has highly effective detoxification systems.
• Exercise supports overall physiological health, including reduced inflammation and improved circulation.
Hot yoga may still feel invigorating, challenging, and enjoyable for many students. But its benefits likely come from movement, cardiovascular challenge, and physiological stress adaptation rather than the elimination of toxins.
Understanding the physiology behind these claims allows us to teach with greater clarity and confidence.
References:
Baker, L. 2019. “Physiology of Sweat Gland Function: The Roles of Sweating and Sweat Composition in Human Health.” Temperature 6 (3): 211–259.
Flynn, M.G., B.K. McFarlin, and M.M. Markofski. 2007. “The Anti-Inflammatory Actions of Exercise Training.” American Journal of Lifestyle Medicine 1 (3): 220–235.
Klein, A.V., and H. Kiat. 2015. “Detox Diets for Toxin Elimination and Weight Management: A Critical Review of the Evidence.” Journal of Human Nutrition and Dietetics 28 (6): 675–686.
Schröder, J., and J. Harder. 2006. “Antimicrobial Skin Peptides and Proteins.” Cellular and Molecular Life Sciences 63 (4): 469–486.
Sears, M., and S. Genuis. 2012. “Environmental Determinants of Chronic Disease and Medical Approaches: Recognition, Avoidance, Supportive Therapy, and Detoxification.” Journal of Environmental and Public Health.
Tabas, I., and C.K. Glass. 2013. “Anti-Inflammatory Therapy in Chronic Disease: Challenges and Opportunities.” Science339 (6116): 166–172.
Watabe, A. et al. 2013. “Sweat Constitutes Several Natural Moisturizing Factors.” Journal of Dermatological Science 72 (2): 177–182.