Hot yoga, what’s the big deal?
I took a visit to a hot yoga studio after I had a frozen shoulder and it recovered my range of movement so quickly I couldn’t believe it. The heat was so helpful for loosening me up and I instinctively felt that it was what I needed. It’s not for everyone and obviously if you don’t like being in the heat then it’s not for you.
Why you should give a go.
You step into a room held at 40°C with 40% humidity, and within minutes you're dripping. It sounds like a form of self-punishment — but the research suggests it might be one of the most comprehensive workouts you can give yourself, body and mind alike.
Bikram yoga — the popular form of hot yoga — was developed in the early 1970s and consists of a fixed sequence of 26 postures and two breathing exercises, performed over 90 minutes.
26 Postures in a single Bikram session
40°C Room temperature (105°F) at 40% humidity
90 Minutes per class, every time although there are faster paced Hot 75 and Hot 60 classes are to be found as well.
What the research actually shows
Strength, flexibility & balance
Published reviews confirm that Bikram yoga measurably improves lower body strength, upper and lower body range of motion, and balance in healthy adults. A 2013 study in the Journal of Strength and Conditioning Research found significant physical fitness gains after just a few weeks of regular practice.
Cardiovascular health & arterial stiffness
The Bikram Yoga Heart Study (University of Texas, Austin) found improvements in endothelium-dependent vasodilation — essentially, how well your blood vessels relax and expand. Separate research found that even 12 hot yoga sessions boosted cardiovascular fitness and heat tolerance. A reduction in LDL cholesterol and body fat was more pronounced in the heated group than in those practicing the same sequence at room temperature.
Depression — landmark Harvard findings
A 2023 randomised controlled trial from Harvard Medical School assigned 65 adults with moderate-to-severe depression to either hot yoga or a waiting list. Those attending even just one 90-minute session per week showed significantly reduced depression symptoms by week eight. Nearly 60% saw a 50% reduction in symptoms, and 44% were considered to be in remission. Researchers believe the heat itself positively affects signalling pathways in the brain — something a standard yoga class may not replicate.
Stress, mindfulness & mental fitness
An 8-week study of 51 participants found that regular Bikram practice improved mindfulness scores, reduced perceived stress, and boosted cardiorespiratory endurance, flexibility, and balance . Mindfulness was negatively correlated with both stress and resting heart rate, suggesting the mental and physical benefits compound one another.
Blood sugar & metabolic markers
Research reports that short-term Bikram practice may improve glucose tolerance, particularly in older adults with obesity. Non-randomised studies also point to improvements in blood lipid profiles, blood pressure, and bone mineral density — though larger, better-controlled trials are still needed to confirm these effects.
Sleep quality
A home sleep monitoring study found that young adults practicing Bikram yoga experienced less night time awakenings. This is a finding consistent with broader research linking exercise-induced heat exposure to deeper, more restorative sleep cycles.
Does the heat actually matter?
This is the interesting question, and the science is nuanced. A 2024 systematic review found that a single session of hot yoga increases core temperature and heart rate compared to unheated yoga, but does not significantly increase overall energy expenditure. In other words, you're not necessarily burning more calories because of the heat.
Where the heat may matter most is cardiovascular adaptation, vasodilation, and the mental health dimension. The Harvard depression trial specifically used hot yoga, and researchers believe thermal exposure activates distinct neurochemical pathways. It's also worth noting that reductions in LDL and body fat in the Bikram Heart Study were more pronounced in the heated group than in those doing the same poses at room temperature.
A typical Bikram class: what you're working on
Standing series (poses 1–12)
Builds strength, balance, and spinal compression from the top down
Floor series (poses 13–26)
Deep backbends, hip openers, and spinal twists with active recovery
Pranayama breathing
Opens the lungs, raises core temperature before postures begin
Savasana (dead body pose)
Practised between poses — importanat for nervous system reset
A note on safety
Hot yoga is safe for most healthy adults, but it does carry elevated cardiovascular demands. A 2024 systematic review flagged case reports of adverse events in those with underlying cardiac conditions. Always hydrate well before and after class, replenish electrolytes (including sodium and calcium), and consult a GP if you have any heart conditions, are pregnant, or are new to vigorous exercise. Listen to your body always - yoga is a personal practice and your body is different every day.
The bottom line
Bikram and hot yoga are among the most research-friendly forms of yoga, precisely because the sequence never changes. The evidence supports real benefits in physical fitness, cardiovascular health, mood, stress reduction, and metabolic markers.
If you've never tried it: go to your first class well-hydrated, wear as little as feels comfortable, and give yourself permission to sit down if you need to. Nothing can quite prepare you for your first class and it’s hard to imagine that you will get used to the heat. It’s a practice to commit to to feel the full benefits.
Sources: PMC / NIH systematic review (2024) · Journal of Clinical Psychiatry (2023, Harvard) · Journal of Exercise Science & Fitness (2011) · Experimental Physiology (2018, UT Austin) · Journal of Strength & Conditioning Research (2013) · PubMed critical review (2015)