Hot Yoga Research and Publications

Citation: Nyer, M. B., Hopkins, L. B., Nagaswami, M., Norton, R., Streeter, C. C., Hoeppner, B. B., et al. (2023). A randomized controlled trial of community-delivered heated hatha yoga for moderate-to-severe depression. The Journal of Clinical Psychiatry, 84(6), 22m14621. Read the original article here. | Read the Harvard Gazette coverage here.

What the study did: Researchers at Massachusetts General Hospital (Harvard Medical School) conducted an 8-week randomized controlled trial with 80 adults diagnosed with moderate-to-severe depression. Participants were randomly assigned to either attend heated yoga classes (90-minute Bikram yoga sessions in a 105°F room) at least twice weekly at community studios, or to a waitlist control group. Depression severity was measured before and after using the clinician-rated Inventory of Depressive Symptomatology (IDS-CR), a gold-standard clinical assessment tool.

What they found: Yoga participants showed a significantly greater reduction in depression symptoms than the waitlist group, with a large effect size (Cohen’s d = 1.04). 59.3% of yoga participants experienced a 50% or greater decrease in symptoms — compared to just 6.3% of the waitlist group. Furthermore, 44% of yoga participants achieved full remission (their depression scores dropped so low they were no longer considered clinically depressed), compared to only 6.3% of the waitlist group. Benefits were observed even in participants who attended only about half the prescribed dose — approximately one class per week.

Why this matters: The 44% remission rate demonstrates that this specific heated yoga sequence can function as a highly effective, non-pharmacological intervention for clinical depression. Because the study specifically used the standardized Bikram yoga sequence and protocol, the findings are directly applicable to the practice taught in Original Hot Yoga studios. The results suggest that even modest engagement (one class per week) can yield clinically meaningful reductions in depressive symptoms.

Citation: La Rocque, C. L., Mazurka, R., Stuckless, T. J. R., Pyke, K. E., & Harkness, K. L. (2021). Randomized controlled trial of bikram yoga and aerobic exercise for depression in women: Efficacy and stress-based mechanisms. Journal of Affective Disorders, 280(A), 457–466. Read the original article here.

What the study did: Researchers at Queen’s University randomly assigned women diagnosed with major depression to one of three groups for 8 weeks: Bikram yoga classes, aerobic exercise, or a waitlist control group. They measured depression symptoms before and after, and also tracked biological stress markers — specifically cortisol levels and patterns of negative thinking (rumination).

What they found: Both the Bikram yoga group and the aerobic exercise group showed significant reductions in depression symptoms compared to the waitlist group. Bikram yoga showed comparable efficacy to aerobic exercise — a treatment already well-established in the clinical literature for depression. The researchers found that both interventions appeared to work, at least in part, by helping participants interrupt negative, ruminative thinking patterns — not just by reducing cortisol or improving physical fitness.

Why this matters: The finding that Bikram yoga reduces depression by interrupting rumination provides a specific psychological mechanism for how the practice works. It indicates that the intense, present-moment attentional demands of the class — the heat, the dialogue, the physical challenge — actively disrupt the brain’s tendency to spiral into repetitive negative thought, functioning as a structured cognitive intervention alongside the physical exercise.

Citation: Hunter, S. D., Laosiripisan, J., Elmenshawy, A., & Tanaka, H. (2018). Effects of yoga interventions practised in heated and thermoneutral conditions on endothelium-dependent vasodilatation: The Bikram yoga heart study. Experimental Physiology, 103(3), 391–396. Read the original article here.

What the study did: Researchers at Texas State University and the University of Texas at Austin randomly assigned 52 sedentary, middle-aged adults (ages 40–60) to one of three groups for 12 weeks: Bikram yoga in a heated room (40.5°C / 105°F), Bikram yoga in a room-temperature environment (23°C / 73°F), or a sedentary control group. They measured endothelium-dependent vasodilation — the ability of blood vessels to dilate in response to increased blood flow — using a precise, non-invasive imaging technique called brachial artery flow-mediated dilation (FMD).

What they found: Both yoga groups showed significant improvements in vascular function compared to the control group. The room-temperature yoga group showed a statistically significant increase in FMD; the heated yoga group showed a strong trend toward improvement. Importantly, the heated group showed significantly greater reductions in body fat percentage than the room-temperature group.

Why this matters: Endothelial function is a primary marker of cardiovascular health that typically declines with age, increasing the risk of heart disease. This study demonstrates that the standardized Bikram yoga sequence meaningfully reverses this age-related decline in middle-aged adults after just 12 weeks, regardless of the room temperature. However, the additional body composition benefits observed only in the heated group support the specific metabolic value of the traditional heated environment.

Citation: Hewett, Z. L., Cheema, B. S., Pumpa, K. L., & Smith, C. A. (2015). The effects of Bikram yoga on health: Critical review and clinical trial recommendations. Evidence-Based Complementary and Alternative Medicine, 2015, 428427. Read the full paper here (open access).

What the study did: Researchers at the University of Canberra systematically gathered and evaluated all published research on Bikram yoga up to 2015, assessed the quality of each study’s design, summarized the findings across all health outcomes measured, and provided recommendations for future research.

What they found: The review confirmed that Bikram yoga improves lower body strength, range of motion, and balance in healthy adults. Beyond physical fitness, the evidence suggested that Bikram yoga may also improve glucose tolerance, bone mineral density, blood lipid profile, arterial stiffness, mindfulness, and perceived stress — particularly in populations with health challenges.

Why this matters: By synthesizing findings across multiple independent studies, this review establishes that the physiological and psychological benefits of Bikram yoga are consistent across different research populations. It confirms that the practice yields measurable improvements across a wide range of health markers, from cardiovascular and metabolic health to psychological wellbeing and bone density.

Citation: Hopkins DeBoer, L. B. (2015). Effects of an 8-week Bikram yoga intervention on depression, anxiety, and potential transdiagnostic mechanisms of action. San Francisco VA Medical Center. Presented at the Anxiety and Depression Association of America (ADAA) Annual Conference, Miami, FL, 2015.

What the study did: Dr. Lindsey Hopkins DeBoer and colleagues at the San Francisco VA Medical Center studied 52 women between the ages of 25 and 45 who were randomly assigned to either an 8-week Bikram yoga program or a waitlist control group. Participants were assessed for depression, anxiety, and several psychological mechanisms thought to underlie both conditions — including mindfulness, distress tolerance, and body image.

What they found: Women in the Bikram yoga group showed significant reductions in both depression and anxiety compared to the waitlist group. The study also found improvements in mindfulness and distress tolerance — the ability to sit with uncomfortable emotions without being overwhelmed by them.

Why this matters: The finding that Bikram yoga improves distress tolerance and mindfulness helps explain the psychological mechanisms behind its effect on anxiety and depression. It suggests that the practice actively builds the same emotional regulation capacities that evidence-based clinical therapies aim to cultivate, making it a valuable tool for individuals struggling to manage difficult internal states.

Citation: Sangiorgio, S. N., Mukherjee, A. K., Lau, N. W., Mukherjee, A., Mukhopadhyay, P., & Ebramzadeh, E. (2014). Optimization of physical activity as a countermeasure of bone loss: a 5-year study of Bikram yoga practice in females. Health, 6(11), 1124–1132. Read the full paper here (open access).

What the study did: Researchers measured bone mineral density (BMD) in nine female Bikram yoga instructors between the ages of 30 and 59, all of whom had been practicing and teaching Bikram yoga for a minimum of three years and continued to do so throughout the study period. Using DEXA scans, they measured BMD at the hip and spine at the start of the study and again five years later.

What they found: Pre-menopausal women showed a mean increase in bone mineral density of 6.6% at the femoral neck, 2.0% at the total hip, and 1.0% at the lumbar spine over five years. Post-menopausal women showed decreases in BMD, consistent with expected age-related bone loss, though the study could not determine if the rate of loss was slowed.

Why this matters: Most weight-bearing exercises that build bone (like running or jumping) also stress the joints, making them unsuitable for many people. This longitudinal study provides evidence that long-term Bikram yoga practice — which is weight-bearing but low-impact — can actively build and preserve bone density in pre-menopausal women, offering a joint-safe countermeasure against future osteoporosis.

Citation: Pate, L., & Buono, M. J. (2014). The physiological responses to Bikram yoga in novice and experienced practitioners. Alternative Therapies in Health and Medicine, 20(4), 12–18.

What the study did: Researchers measured energy expenditure, heart rate, and sweat rate in 24 healthy male and female practitioners during a standardized 90-minute Bikram yoga class. Participants were classified as either novice or experienced to compare how physiological responses change with practice history.

What they found: The mean absolute energy expenditure for the 90-minute session was 286 ± 72 kcals. Experienced practitioners exhibited a higher relative energy expenditure (4.7 vs. 3.7 kcal/kg), a higher percentage of predicted maximum heart rate (86.4% vs. 72.3%), and a higher sweat rate (1.1 vs. 0.6 kg/h) compared to novices. The average intensity across all postures was 2.9 METs (light-to-moderate intensity).

Why this matters: This study quantifies the caloric and cardiovascular demands of the practice, confirming it qualifies as light-to-moderate intensity exercise. Crucially, it demonstrates that as practitioners gain experience and skill, they are able to work harder and generate a more intense physiological response, meaning the practice continues to offer physical challenges even after years of experience.

Citation: Fritz, M. L., et al. (2013). Acute metabolic, cardiovascular, and thermal responses to a single session of Bikram yoga. Proceedings of the Rocky Mountain ACSM Annual Meeting, Denver, CO.

What the study did: This study quantified the immediate physiological demands of a single 90-minute Bikram yoga session by measuring energy expenditure, heart rate, and peak core body temperatures in participants throughout the class.

What they found: A single session resulted in a total energy expenditure of 378 ± 78 kcal (averaging 333 kcal for females and 459 kcal for males). Peak core body temperatures increased by an average of 0.8°C from baseline, reaching 38.2 ± 0.3°C (approx. 100.8°F) around 50 minutes into the session.

Why this matters: These findings provide clear, quantitative data on the thermal stress and caloric expenditure experienced during a standard class. Understanding that core temperature rises safely but measurably helps practitioners make informed decisions about hydration and pacing during the practice.

Citation: Hunter, S. D. (2013). Improvements in glucose tolerance with Bikram yoga in older obese adults: a pilot study. Journal of Bodywork and Movement Therapies, 17(4), 404–407.

What the study did: Fourteen young lean adults and 15 older obese adults participated in an 8-week Bikram yoga intervention, attending classes three times per week. Glucose tolerance was assessed before and after the intervention using a 75g oral glucose tolerance test (OGTT).

What they found: In the older obese subjects, the area under the glucose curve following the OGTT was significantly reduced after the 8-week intervention, indicating improved glucose tolerance. In plain terms, this means that after drinking the sugar solution, their blood sugar rose less sharply and returned to normal more quickly — a sign that the body is managing insulin and blood sugar more efficiently, which is the core measure of diabetes risk. They also observed small but significant reductions in body mass and BMI. No such changes were observed in the young lean subjects, whose glucose tolerance was already optimal.

Why this matters: This study demonstrates that regular Bikram yoga practice can effectively improve glucose tolerance in older, obese individuals who are at higher risk for metabolic diseases like type 2 diabetes. It positions the practice as a viable non-pharmacological intervention for improving metabolic health in vulnerable populations.

Citation: Hunter, S. D., et al. (2013). The effect of Bikram yoga on arterial stiffness in young and older adults. Journal of Alternative and Complementary Medicine, 19(12), 930–934.

What the study did: Researchers investigated the effects of an 8-week Bikram yoga intervention (three classes per week) on arterial stiffness and insulin resistance in 24 young adults and 18 older adults. Measurements included blood pressure, fasting blood glucose, cholesterol levels, carotid artery compliance, and arterial stiffness.

What they found: Young adults experienced increased carotid artery compliance and decreased arterial stiffness. Older adults did not show changes in arterial stiffness, but did show significant decreases in insulin resistance and total cholesterol levels. Both groups demonstrated increased trunk flexibility.

Why this matters: The findings show that Bikram yoga provides distinct cardiovascular and metabolic benefits depending on age. For young adults, it improves the physical elasticity of the arteries; for older adults, it improves metabolic markers like insulin resistance and cholesterol profiles, both of which are critical for long-term health.

Citation: Tracy, B. L., & Hart, C. E. F. (2013). Bikram yoga training and physical fitness in healthy young adults. Journal of Strength and Conditioning Research, 27(3), 822–830.

What the study did: Ten healthy young adults completed 24 Bikram yoga sessions over 8 weeks, while a control group maintained their normal routine. Researchers measured isometric deadlift strength, handgrip strength, lower back/hamstring and shoulder flexibility, resting heart rate, maximal oxygen consumption, and body composition.

What they found: The yoga group demonstrated increased deadlift strength, substantially increased lower back/hamstring and shoulder flexibility, and a modest decrease in body fat. No significant changes were observed in cardiovascular measures or maximal aerobic fitness.

Why this matters: This study confirms that consistent Bikram yoga practice effectively improves musculoskeletal fitness — specifically strength and flexibility — even in already healthy young adults. It clarifies that while the practice is cardiovascularly demanding, its primary physical adaptations occur in the musculoskeletal system rather than in maximal aerobic capacity.

Citation: Abel, A. N., et al. (2012). Physiological characteristics of long-term Bikram yoga practitioners. Journal of Exercise Physiology Online, 15(5), 32–39.

What the study did: This cross-sectional study compared the resting heart rate, blood pressure, lung function, and aerobic fitness of 31 Bikram yoga practitioners, divided into two groups: those with less than 3 months of experience, and those with one year or more of experience.

What they found: The study found no significant differences in resting heart rate, blood pressure, lung function, or aerobic fitness between the short-term and long-term practitioners. The average VO2 max for all practitioners was 35 ml·kg-1·min-1.

Why this matters: These findings suggest that while practitioners may exhibit healthy baseline cardiovascular markers, continuing the practice for years does not necessarily lead to progressive, compounding improvements in resting hemodynamics or aerobic capacity beyond the initial adaptations. It reinforces that Bikram yoga is primarily a musculoskeletal and metabolic intervention rather than a progressive aerobic training program.

Citation: Kudesia, R. S., & Bianchi, M. T. (2012). Decreased nocturnal awakenings in young adults performing Bikram yoga: a low-constraint home sleep monitoring study. ISRN Neurology, 2012, 153745.

What the study did: This 14-day observational study investigated the impact of Bikram yoga on sleep in 13 healthy young adults. Participants monitored their sleep using daily diaries and a headband sleep device, allowing researchers to compare objective sleep metrics on days they practiced yoga versus days they did not.

What they found: While total sleep time and sleep stages were unaffected, Bikram yoga was associated with a significantly faster return to sleep after waking up in the night. Specifically, the time it took to fall back asleep was 25% faster on yoga days.

Why this matters: This study provides objective evidence that Bikram yoga improves sleep architecture by facilitating a more rapid return to sleep after nocturnal awakenings. For individuals who struggle with fragmented sleep or middle-of-the-night insomnia, the practice may offer a non-pharmacological way to improve sleep stability.

Citation: Hewett, Z. L., et al. (2011). An examination of the effectiveness of an 8-week Bikram yoga program on mindfulness, perceived stress, and physical fitness. Journal of Exercise Science and Fitness, 9(2), 87–92.

What the study did: Fifty-one participants completed an 8-week Bikram yoga program (attending a minimum of 20 sessions). Researchers measured changes in mindfulness, perceived stress, resting heart rate, and various markers of physical fitness (flexibility, balance, and cardiorespiratory endurance) before and after the program.

What they found: The 8-week program significantly improved mindfulness, perceived stress, cardiorespiratory endurance, flexibility, and balance. Furthermore, increases in mindfulness were directly correlated with decreases in perceived stress and resting heart rate.

Why this matters: This study demonstrates the interconnected nature of the physical and psychological benefits of the practice. It shows that as practitioners develop greater mindfulness through the discipline of the sequence, they experience a corresponding drop in their subjective experience of stress, making it an effective intervention for chronic stress management.

Citation: Hart, E. F., & Tracy, B. L. (2008). Yoga as steadiness training: effects on motor variability in young adults. Journal of Strength and Conditioning Research, 22(5), 1659–1669.

What the study did: Ten young adults completed 24 Bikram yoga sessions over 8 weeks, while a control group maintained their usual activity. Researchers measured maximum voluntary contraction force of the leg and arm muscles, steadiness of muscle contractions, and timed balance.

What they found: The yoga group showed a 14% increase in leg strength (knee extensor force) and a massive 228% improvement in balance time. Individuals who started with the lowest baseline steadiness in their leg muscles experienced the greatest improvements in motor control.

Why this matters: This study highlights Bikram yoga’s specific effectiveness as neuromuscular steadiness training. The dramatic improvements in balance and leg muscle control suggest the practice is highly effective at training the nervous system to recruit muscle fibers more efficiently, which is crucial for stability and fall prevention.

Citation: Steiger, H. (2004). Eating disorders and the serotonin connection: state, trait and developmental effects. Journal of Psychiatry & Neuroscience, 29(1), 20–29. Read the full paper here (open access).

If you have ever wondered why eating disorders are so often accompanied by anxiety, perfectionism, or impulsivity, the answer likely lies in a single brain chemical: serotonin.

Dr. Howard Steiger’s landmark 2004 paper fundamentally changed how we understand eating disorders. Rather than viewing them simply as behavioral problems related to food, Steiger proposed that eating disorders are the result of a complex collision between our biology, our personality traits, and our life experiences — all converging on the brain’s serotonin system. His central argument is that serotonin levels in a person with an eating disorder are shaped by three interacting factors:

1. State Effects (The immediate impact of diet): Serotonin is made from tryptophan, an amino acid we get from food. When a person restricts their diet, their brain literally cannot make enough serotonin. This creates a temporary “state” of low serotonin, which can trigger binge eating, depression, or heightened anxiety.

2. Trait Effects (Our constitutional wiring): Some people are born with a brain that is naturally wired to produce either too much or too little serotonin activity. These underlying biological traits show up as personality characteristics. People with high serotonin activity tend toward perfectionism, compulsivity, and over-control — and are more vulnerable to restrictive anorexia nervosa. People with low serotonin activity tend toward impulsivity and under-control — and are more vulnerable to bulimia and binge eating.

3. Developmental Effects (The impact of trauma): Severe stress or trauma during childhood can permanently alter how the serotonin system develops, leaving it highly sensitive and prone to dysregulation later in life.

Crucially, Steiger found that people who recover from restrictive anorexia often continue to show elevated serotonin levels and perfectionistic traits long after their weight is restored — suggesting that their brains are constitutionally highly sensitive to serotonin. The eating disorder is not the cause of the high serotonin; the high serotonin is a pre-existing trait that makes the person vulnerable to the disorder.

The most important clinical takeaway: eating disorders driven by a deep constitutional serotonin sensitivity require interventions that directly support the nervous system — whether through targeted therapy, somatic practices like yoga, or pharmacological support. Simply restoring normal eating is not enough.

Citation: Barbarich, N. (2002). Is there a common mechanism of serotonin dysregulation in anorexia nervosa and obsessive compulsive disorder? Eating and Weight Disorders — Studies on Anorexia, Bulimia and Obesity, 7, 221–231. Read the abstract here.

It is well-documented that individuals with anorexia nervosa frequently experience obsessive-compulsive symptoms, and conversely, many individuals with OCD struggle with eating and body image. But why do these two conditions overlap so frequently?

Barbarich’s 2002 review gathered evidence from neuroimaging, drug trials, and biochemical studies to propose a unifying theory: both conditions are driven by a fundamental dysregulation of the brain’s serotonin system. The paper highlights a crucial paradox: while low serotonin is associated with depression and impulsivity, high serotonin activity is strongly correlated with obsessive, compulsive, and rigidly controlled behavior — exactly the patterns seen in both anorexia and OCD.

One of the most profound implications of this research is how it reframes the act of starvation in anorexia. If a person’s brain is constitutionally wired to produce too much serotonin — resulting in a constant, uncomfortable state of high anxiety and obsessionality — starvation actually provides temporary relief. Because serotonin is synthesized from tryptophan (found in food), severe calorie restriction starves the brain of the building blocks needed to make serotonin. In this light, restrictive eating is not merely a pursuit of thinness; it is an unconscious, biological attempt to self-medicate a hyperserotonergic brain.

Understanding this shared biological root changes how we approach treatment: recovery requires more than weight restoration. It requires tools to manage the anxiety and obsessionality that will return when eating is normalized — tools such as nervous system regulation practices, somatic therapies, and when appropriate, pharmacological support.

Citation: Streeter, C. C., et al. (2007). Yoga Asana sessions increase brain GABA levels: a pilot study. The Journal of Alternative and Complementary Medicine, 13(4), 419–426. Read the original article here.

In 2007, researchers at Boston University School of Medicine published a landmark study demonstrating that a single 60-minute yoga session increased brain levels of GABA (Gamma-aminobutyric acid) by 27%. A control group that spent 60 minutes reading showed no change in GABA levels.

GABA is the brain’s primary inhibitory neurotransmitter — the chemical responsible for calming the nervous system, reducing excitability, and promoting relaxation. Low GABA levels are strongly associated with anxiety, depression, and stress disorders. Many anti-anxiety medications (such as benzodiazepines) work specifically by enhancing GABA activity in the brain. This study provided the first direct neuroimaging evidence — using magnetic resonance spectroscopy — that yoga practice naturally and significantly boosts this exact same calming chemical.

When you leave the hot room feeling a profound sense of calm, clarity, and reduced anxiety, it is not just a psychological shift or an endorphin rush from the workout. Your brain chemistry has fundamentally changed. The practice actively generates the neurotransmitters required to quiet an overactive, anxious mind.

Hot Yoga’s Benefits May Not Come from the Heat at All (Forbes Magazine, 2018)
A mainstream look at research showing that the cardiovascular benefits of the practice occur regardless of room temperature, though the heated room provides additional benefits for LDL cholesterol and body fat reduction.

Bikram Yoga doesn’t need hot room to benefit heart health (Reuters, 2018)
Coverage of the Hunter et al. study demonstrating how the specific sequence of postures improves endothelial function and arterial stiffness.

Teacher: Experience Needed (New York Times, 2011)
A compelling human-interest piece exploring how the intense discipline and focus required in the hot room can serve as a powerful tool for those in addiction recovery.

Sitting Down In Bikram Yoga: What it Says About You
A thoughtful reflection on the psychological resistance to resting during class, and what we learn when we finally allow ourselves to sit down.

F*** Neoliberal Yoga: Selling Yoga and Selling Ourselves in the Digital Age (Part I and Part II)
A critical look at the commercialization of modern yoga culture and how it impacts our relationship to the practice.

Selected writings from our studio blog exploring the deeper dimensions of the practice:

• Leaving the Prison of Pain or Nothingness
• There is No Such Thing as Monday
• Big Girls Bend: My (Ongoing) Journey as a Fat Yogi
• When Will I Be Able to DO the Posture?
• This Body Is the Earth: Bikram Yoga as a Tool for Reconnection

An exploration of how the human species has lost the ability to breathe properly, and how we can fix it. Highly relevant to the pranayama and breathing techniques central to our practice.

A narrative introduction to the Yoga Sutras of Patanjali, explaining the ancient philosophy of yoga through an accessible, engaging story.

A groundbreaking look at the mind-body connection in chronic pain, particularly how repressed emotions manifest as physical tension and back pain.

A yogi’s guide to joy, offering practical wisdom for managing your mind, body, and energies to create a life of profound well-being.

A surgeon’s profound look at aging, death, and how medicine can not only improve life but also the process of its ending.

A powerful memoir by a Holocaust survivor and psychologist about the human capacity to heal from trauma and choose freedom over victimhood.

A practical guide to identifying and dismantling the self-limiting beliefs and mental prisons that keep us from living fully.

A philosophical and personal exploration of chronic illness, healing, and the limitations of the modern medical paradigm.