The authors of a 2022 trial noted that most research on passive heat had used hot water or traditional saunas, mostly in men, rather than infrared saunas. Infrared cabins run cooler, so those findings don’t transfer automatically.
This page covers what trials of infrared saunas themselves have measured. It is general information, not medical advice. If you’re choosing a cabin, the infrared sauna buying guide covers heaters, power, and size.
Short answer: the strongest infrared evidence comes from Japanese “Waon therapy” trials in heart failure. A 2016 randomized trial of 149 patients found better symptoms and walking distance after 10 daily sessions, though its main blood marker didn’t change significantly. Smaller studies report short-term relief for arthritis and fibromyalgia pain. Most studies are small and many had no control group.
What Cleveland Clinic says
Cleveland Clinic lists six possible benefits of infrared saunas: heart health, sore muscles, pain relief, relaxation, sleep, and immunity. It also says more research is needed, especially on infrared saunas, to know whether they directly improve heart health.
It gives the typical infrared range as 110 to 135°F (43 to 57°C), cooler than the 150 to 195°F of a traditional sauna.
The heart failure trials
Waon therapy, which its developers describe as “soothing warmth therapy,” was developed in Japan as a treatment for heart failure. Patients sit in a far-infrared sauna at 60°C (140°F) for 15 minutes, then rest under a blanket for 30 minutes.
Tei (2016) ran the WAON-CHF trial at 19 hospitals, published in Circulation Journal. It randomized 149 hospitalized patients with advanced heart failure to 10 daily sessions or standard care alone.
| Outcome after 10 days | Waon group vs control |
|---|---|
| Symptom class (NYHA) | Improved only in the Waon group |
| 6-minute walk distance | Improved only in the Waon group |
| Heart size on X-ray | Improved only in the Waon group |
| BNP blood marker (main endpoint) | Change not statistically significant |
| Serious adverse events | None in either group |
The authors concluded:
“Waon therapy, a holistic soothing warmth therapy, showed clinical advantages in safety and efficacy among patients with advanced HF.”
Tei C et al., Circulation Journal, 2016
Pain, arthritis, and fibromyalgia
Oosterveld (2009) gave 34 people with rheumatoid arthritis or ankylosing spondylitis 8 infrared sessions over 4 weeks, in Clinical Rheumatology. Pain and stiffness fell significantly during sessions. Over the 4 weeks, the improvements did not reach statistical significance. No one’s disease flared.
Matsushita (2008) treated 13 women with fibromyalgia using Waon therapy, in Internal Medicine. Pain dropped by about half after the first session. There was no control group.
Blood pressure and body temperature
Kominami (2021) reviewed the records of 31 inpatients with high blood pressure who had Waon therapy, in Medicine. Blood pressure fell after single sessions and, among the 11 non-smokers, after repeated sessions. There was no control group.
Jenkins (2026) put 12 healthy adults in a far-infrared sauna at 65°C (149°F) for 45 minutes, in Experimental Physiology. Rectal temperature rose 1.4°C, heart rate climbed from 74 to 153 bpm, and two people stopped early from extreme discomfort.
Limitations
The heart failure trials took place in hospitals, under supervision, with patients still on their usual medication. Kihara (2009), a 5-year Waon study, compared treated patients with a matched group rather than randomizing them. The pain and blood pressure studies had 13 to 34 people. None of these studies tested a home cabin used without supervision.
Here’s what the spec sheet won’t tell you. The six cabins in our temperature guide top out at 140 to 170°F, at or above the 60°C (140°F) of the Waon trials, but no trial we found tested a higher temperature for a health outcome.
Who should check with a doctor first
Cleveland Clinic advises checking with your healthcare provider before starting an infrared sauna routine if you have a pre-existing condition. It says many people with multiple sclerosis are sensitive to heat, and that sauna use, especially early in pregnancy, can be harmful to the fetus.
My rule of thumb: buy an infrared cabin because you enjoy the heat, and treat the trial results as encouraging rather than proven.
Bottom line: infrared saunas have promising but small trials, strongest for supervised heart failure care in Japan, with short-term pain relief in arthritis and fibromyalgia. For cabins, see the infrared sauna buying guide linked above.
Sources
- Cleveland Clinic, “6 Possible Benefits of Infrared Saunas,” October 9, 2026: health.clevelandclinic.org
- Tei C et al., “Waon Therapy for Managing Chronic Heart Failure: Results From a Multicenter Prospective Randomized WAON-CHF Study,” Circulation Journal, 2016;80:827-834 (abstract): pubmed.ncbi.nlm.nih.gov
- Kihara T et al., “Waon therapy improves the prognosis of patients with chronic heart failure,” Journal of Cardiology, 2009;53:214-218 (abstract): pubmed.ncbi.nlm.nih.gov
- Oosterveld FG et al., “Infrared sauna in patients with rheumatoid arthritis and ankylosing spondylitis,” Clinical Rheumatology, 2009;28:29-34 (abstract): pubmed.ncbi.nlm.nih.gov
- Matsushita K, Masuda A, Tei C, “Efficacy of Waon therapy for fibromyalgia,” Internal Medicine, 2008;47:1473-1476 (abstract): pubmed.ncbi.nlm.nih.gov
- Kominami K et al., “Blood pressure-lowering effect of repeated Waon therapy in non-smokers with hypertension,” Medicine, 2021;100:e26266: europepmc.org
- Hussain JN, Cohen MM, Mantri N, O’Malley CJ, Greaves RF, “Infrared sauna as exercise-mimetic? Physiological responses to infrared sauna vs exercise in healthy women: A randomized controlled crossover trial,” Complementary Therapies in Medicine, 2022;64:102798 (abstract): pubmed.ncbi.nlm.nih.gov
- Jenkins EJ et al., “Far-infrared sauna exposure at 65°C elevates core temperature,” Experimental Physiology, 2026: europepmc.org