The hot yoga depression study run at Massachusetts General Hospital randomised 80 adults with moderate-to-severe depression to eight weeks of heated yoga or a waitlist. Among the 65 people analysed, 59.3% of the yoga group cut their symptoms by half or more, against 6.3% on the waitlist.
That is a striking result, but a headline number only helps when you know how it was produced. This guide walks through the trial's methods, sample, dose and limits. That way you can judge what the hot yoga depression study does and does not tell you.
The Hot Yoga Depression Study at a Glance
The trial was led by Nyer and colleagues and published in the Journal of Clinical Psychiatry in 2023. Its title describes heated hatha yoga delivered in the community. News outlets often call it the MGH hot yoga trial or the heated yoga depression study.
The authors framed it as a test of feasibility, acceptability and preliminary efficacy. That wording matters, because it shows the team saw the hot yoga depression study as an early, promising step and not a final verdict.
The US National Center for Complementary and Integrative Health funded the work, and the trial is registered as NCT02607514. Here are the core facts from the published abstract:
- Design. An 8-week randomised controlled trial of heated yoga versus a waitlist control, run from March 2017 to August 2019.
- Sample. 80 adults were randomised and 65 were analysed (33 in the yoga group, 32 on the waitlist). The mean age was 32.7 years and 81.5% were female.
- Primary measure. The change in the Inventory of Depressive Symptomatology, Clinician Rated (IDS-CR), from baseline to week 8.
- Result. 59.3% of the yoga group (16 people) had a drop of 50% or more on the IDS-CR, versus 6.3% (2 people) on the waitlist.
- Effect size. Cohen's d of 1.04 with P below .001, which counts as a large effect by the usual convention.
How the Trial Was Run: Dose, Heat and Setting
Each session lasted 90 minutes in a room heated to 105°F, which is about 40.6°C, according to the Harvard Gazette report on the trial. Participants were prescribed at least two classes a week for eight weeks. So the hot yoga depression study tested a real-world schedule, not a laboratory routine, which makes its findings easier to apply.
The classes took place at two community studios. That makes the hot yoga depression study unusually practical, because people practised in the same kind of room any reader can walk into.
Participants who were on a stable antidepressant dose could take part, according to the Mass General Brigham psychiatry summary. Both groups kept their usual care. In other words, the trial tested yoga as an addition to existing treatment and not as a replacement for it.
| Trial element | What the study did | Why it matters |
|---|---|---|
| Design | Randomised controlled trial, heated yoga versus waitlist | Random assignment reduces the chance that the groups differed from the start |
| Sample | 80 randomised, 65 analysed, mean age 32.7, 81.5% female | Results may not carry over to men, older adults or milder low mood |
| Dose prescribed | At least two 90-minute classes per week for 8 weeks | Close to a normal studio routine |
| Dose attended | Average of 10.3 classes (SD 7.1) over 8 weeks | Real attendance was lower than the prescription |
| Heat | 105°F (about 40.6°C) room | Humidity was not reported in the abstract |
| Primary outcome | IDS-CR, scored by a clinician | Scored by a clinician, not only self-reported |
| Control | Waitlist, then yoga after 8 weeks | Shows yoga beats waiting, not yoga beats other exercise |
Why the waitlist design deserves a closer look
The waitlist design matters. People on the waitlist continued their normal treatment and then received the yoga programme after the eight weeks ended. That is fair to them, and it is common in behavioural trials. However, it also means the comparison group knew they were not getting yoga yet.
What the 59.3% Figure Means in the Hot Yoga Depression Study
Response is not the same as remission
A response in this trial meant a drop of at least 50% on the IDS-CR. That does not mean symptoms disappeared. Someone with a score of 36 who fell to 18 would count as a responder, yet could still have noticeable symptoms. That is a meaningful change, but it is still different from recovery.
In numbers, 16 people in the yoga group met the response mark compared with 2 on the waitlist. Those counts are small, so each person moves the percentage a lot. This is one reason we keep the language careful when we describe the hot yoga depression study.
The effect size is large, but the sample is small
A Cohen's d of 1.04 means the yoga group improved by about one standard deviation more than the waitlist group. Statisticians call that large. However, large effects in small early trials often shrink when bigger studies test them. So the number from the hot yoga depression study is best treated as a reason to keep researching.
What 10.3 classes tells you about dose
Participants attended an average of 10.3 classes over the eight weeks, which is roughly one class per week even though two were prescribed. The authors concluded that about one heated session per week went with a significantly larger drop in symptoms than waiting. The Harvard Gazette summary also notes that symptoms fell even for people who received only half of the prescribed dose.
For a practical view of weekly frequency, see our guide on how often to do Bikram yoga. The short version is that consistency mattered more than perfection in this trial.
Why the waitlist result matters
Only 6.3% of the waitlist group reached a response. As a result, that low figure shows that time alone, plus usual care, did not produce the same change. Even so, a waitlist cannot rule out expectation effects. People who are told they will start yoga soon may feel different from people who already know they will not.
Limits of the Hot Yoga Depression Study
Every good trial has limits, and this one states several. We list them plainly because readers deserve to know where the evidence stops.
- No active control. The comparison was a waitlist, not another kind of exercise. The authors say further research should use active control conditions.
- Heat is not isolated. The study cannot say whether the heat added anything beyond yoga itself. Senior author Mischoulon told the Harvard Gazette that future work should compare heated and non-heated yoga directly.
- Small and short. 65 people were analysed over eight weeks, and the abstract reports no long-term follow-up.
- Dropout. 15 of the 80 randomised adults were not analysed, and the abstract does not give the reasons.
- Narrow sample. The group was mostly women with an average age under 33, and everyone chose to try hot yoga.
- No blinding. Nobody can be blinded to whether they are doing yoga, which leaves room for expectation to play a part.
None of this makes the hot yoga depression study weak. It makes it preliminary, which is exactly how its authors describe it. To explore the heat question, read our article on hot yoga versus regular yoga, which covers what laboratory studies say the heat adds.
Please remember that this article is not medical advice. Depression is a medical condition, so consult a healthcare professional about any treatment decision. The abstract also reports only the depression result, which is why we don't stretch the findings to anxiety here.
Does the Hot Yoga Depression Study Apply to Bikram or 26&2 Yoga?
The paper's title says heated hatha yoga. Harvard and Mass General Brigham news coverage describes the classes as Bikram yoga. Public summaries don't say which teachers or class scripts were used. So we can't claim the hot yoga depression study tested one particular dialogue.
What we can do is compare the published conditions with a typical YogaFX class. The match on length and temperature is close. The match on format is plausible but unconfirmed.
| Feature | Hot yoga depression study | A YogaFX 26&2 class |
|---|---|---|
| Class length | 90 minutes | 90 minutes |
| Room temperature | 105°F (about 40.6°C) | 40°C |
| Humidity | Not stated in the abstract | 40%, natural tropical heat |
| Format | Heated hatha yoga in two community studios | Fixed 26 postures and 2 breathing exercises, scripted dialogue, no demonstration or music |
| Frequency | At least two classes per week prescribed | Student's choice |
So the honest reading is this: the trial studied a heated, 90-minute practice at around 40°C, and a YogaFX class shares those basics. It does not follow that a YogaFX class would produce the same numbers. For more on temperature and humidity, see our guide to the Bikram hot yoga room.
For the wider picture, our companion guide Bikram yoga for depression: what the research shows looks at the same trial from the practitioner's side. This article stays on the methods and the numbers.
What YogaFX Students Say About Focus and Mood
Student reviews are personal experiences, not research. They cannot confirm anything about depression. Still, they show what regular practice feels like from the inside. Here are two reviews from our Google profile, quoted word for word.
More focus inside myself, more positive mindset and motivated. Thanks Ian for the class!
Nur, Google review, 2018
The personal interaction to all his student as individuals is exemplary and respectful, reassuring and brings out the confidence in the most reluctant and doubtful student.
Konrad, Google review, 2025
Both reviewers mention structure, attention from the teacher and a feeling of confidence. Because those themes are common in what students tell us, we share them here. We wouldn't claim they explain the results of the hot yoga depression study. They do remind us that a class is more than heat and movement.
How to Read a Trial Like the Harvard Hot Yoga Study
People often call this paper the Harvard hot yoga study, because Massachusetts General Hospital is a Harvard teaching hospital. You don't need a statistics degree to read a trial like this one. Five plain questions will take you most of the way.
Who was studied?
Adults with moderate-to-severe depression, mostly women, with an average age of 32.7. For example, the hot yoga depression study speaks best to people like them. It says less about teenagers, older adults or mild low mood.
What was compared?
Heated yoga was compared with a waitlist. That tells you yoga did better than waiting. It doesn't tell you yoga did better than walking, swimming or an unheated class, because those weren't tested.
How was the outcome measured?
A clinician scored symptoms on the IDS-CR at the start and at week eight. Because a trained rater did the scoring, the result doesn't rest on a self-rating alone. Still, raters in a yoga trial usually know who did the yoga, so some bias can remain.
How big and how long was it?
Sixty-five people were analysed over eight weeks. That's enough to detect a large effect, but it's small next to the big drug trials. For that reason, a heated yoga depression study like this one is best read as a first step. We'd want larger replications before anyone calls it settled.
Who ran it and paid for it?
The team worked at Massachusetts General Hospital, a Harvard teaching hospital, and a US government institute funded it. The trial was also registered publicly as NCT02607514. None of that guarantees the result, but it does show the work followed normal research channels.
How to Use the Hot Yoga Depression Study Responsibly
The hot yoga depression study gives you information, not a prescription. If this research makes you curious about heated yoga, these steps match what the trial did and what its authors say.
- Talk to your doctor first. This matters most if you take medication, have heart or blood pressure concerns, or are pregnant. Heat places real demands on the body, so check first.
- Keep your existing care. Participants continued their usual treatment, and the trial tested yoga as an addition.
- Aim for steady attendance. The trial prescribed two classes a week, and people attended about one on average. Build up at a pace you can keep.
- Start gently with the heat. Hydrate well, rest when you need to, and leave the room if you feel dizzy, because heat affects everyone differently.
- Choose a consistent format. A class with the same length and temperature each time is closest to the studied setup.
- Track how you feel. Share changes in mood, sleep and energy with your doctor or therapist.
If you are thinking about harming yourself, contact your local emergency number or a crisis line right away. Exercise is not an emergency response.
YogaFX and Mr. Ian Terry: Teaching From the Evidence
Mr. Ian Terry, E-RYT 500 and founder of YogaFX, has more than 12,000 teaching hours and has trained over 1,500 graduates from 80-plus countries. Our approach under his lead is to present studies like this one as context for students, never as a promise. Teachers who understand both the postures and the research can, for instance, hold a heated room more responsibly.
That matters for future teachers. The six-day hybrid YogaFX programme combines pre-course online study with an intensive in Bali. It leads to Yoga Alliance RYT 200-Hour registration plus the Bikram Hot 26&2 200-Hour International Yoga Certification. You can read the details in our guide to Bikram yoga teacher training dates, cost and formats.
FAQ
Does hot yoga help with depression?
In the Massachusetts General Hospital trial, 59.3% of adults with moderate-to-severe depression who did heated yoga for eight weeks cut their symptoms by half or more, versus 6.3% on a waitlist. It is preliminary evidence from 65 analysed people, so it supports further research rather than proving a treatment.
How long was the hot yoga depression study?
The intervention lasted eight weeks. Participants were prescribed at least two 90-minute heated classes per week, although they attended an average of 10.3 classes in total. The trial itself ran from March 2017 to August 2019, and symptoms were measured at baseline and again at week eight with a clinician-rated scale.
How hot was the room in the hot yoga depression study?
Harvard and Mass General Brigham summaries describe a 105°F room, about 40.6°C, with 90-minute classes. The published abstract does not report humidity. A YogaFX class runs at 40°C and 40% humidity using natural tropical heat, so the temperature is similar, though the trial classes and ours are not identical.
Can hot yoga replace antidepressants or therapy?
No. In the trial, people on a stable antidepressant dose could take part, and both groups continued their usual care. The study tested yoga as an addition, not a replacement. Please talk with your doctor or mental health professional before changing any treatment, and use heated classes only alongside their advice.
Is the hot yoga depression study proof that heat matters?
Not yet. The trial compared heated yoga with a waitlist, not with yoga in an unheated room, so it cannot separate the effect of heat from the effect of yoga. The authors say future studies should test that directly, which is why we treat the findings as promising, not final.
Still have questions? Message Mr. Ian and the YogaFX team on WhatsApp and we will answer them personally.
