The claim
“Infrared sauna therapy treats heart failure.”
Early. In the largest randomized trial, two weeks of Waon therapy, which pairs a 60°C infrared sauna with rest under a warm blanket, improved walking distance in heart-failure patients. The trial missed its main goal of lowering the heart-strain marker BNP more than standard care, and nearly all the research comes from one Japanese network.
Updated Sep 24, 2026 · 1 study reviewed
Some human data and a plausible mechanism. It needs better trials before anyone can lean on it.
People say it in places like these
Medical reviews
Infrared sauna brings short-term improvement in heart function for people with heart failure.
See an example ↗Infrared sauna brands
Doctors in Japan use infrared therapy to treat heart failure.
Sauna buying guides
Waon therapy improved cardiac markers in heart-failure patients.
The research found this
Waon therapy comes from Japan. Patients sit for 15 minutes in a far-infrared dry sauna held at 60°C and then lie under a warm blanket for 30 minutes.Source 1 · Randomized trialWaon Therapy for Managing Chronic Heart Failure – Results From a Multicenter Prospective Randomized WAON-CHF Study –Tei C, Imamura T, Kinugawa K, et al.. Circulation Journal, 2016.Read the paper ↗PubMed ↗ In an early study of 34 patients with severe heart failure, one session raised heart rate by 20 to 25 beats a minute and lowered filling pressures in the heart.Source 2 · Clinical trialAcute Hemodynamic Improvement by Thermal Vasodilation in Congestive Heart FailureTei C, Horikiri Y, Park JC, et al.. Circulation, 1995.Read the paper ↗PubMed ↗ The heart pumped better afterward.
Small studies in the 2000s reported gains after two to four weeks of daily sessions. In one, symptoms improved in 17 of 20 treated patients and artery widening improved too. Ten untreated patients showed no change.Source 3 · Clinical trialRepeated sauna treatment improves vascular endothelial and cardiac function in patients with chronic heart failureKihara T, Biro S, Imamura M, et al.. Journal of the American College of Cardiology, 2002.Read the paper ↗PubMed ↗ A multicenter study of 188 patients found that BNP fell from 542 to 394 pg/mL with Waon, and its abstract reports no direct test against the control group.Source 4 · Randomized trialBeneficial effects of Waon therapy on patients with chronic heart failure: Results of a prospective multicenter studyMiyata M, Kihara T, Kubozono T, et al.. Journal of Cardiology, 2008.Read the paper ↗PubMed ↗ BNP is a blood marker that rises when the heart is under strain.
The largest test was the WAON-CHF trial. At 19 Japanese hospitals, 149 patients with advanced heart failure were randomized to ten Waon sessions over two weeks or to the same medical care without it.Source 1 · Randomized trialWaon Therapy for Managing Chronic Heart Failure – Results From a Multicenter Prospective Randomized WAON-CHF Study –Tei C, Imamura T, Kinugawa K, et al.. Circulation Journal, 2016.Read the paper ↗PubMed ↗ The primary endpoint was the change in BNP compared between groups, and it showed no difference (P = 0.4179). Six-minute walking distance rose by 44.9 meters with Waon against 12.7 meters in controls, and heart size on chest X-ray shrank a little more.
A 2018 meta-analysis pooled seven Waon studies with 491 patients and found lower BNP and a 1.45-point rise in ejection fraction over two to four weeks.Source 5 · Meta-analysisEffects of sauna bath on heart failure: A systematic review and meta‐analysisKällström M, Soveri I, Oldgren J, et al.. Clinical Cardiology, 2018.Read the paper ↗PubMed ↗ None of the studies was blinded, and eight of the nine it reviewed came from Japan. Waon's developer was one of its authors.
Survival data come from one hospital. After five years, heart-failure readmission or cardiac death had occurred in 31.3% of 64 Waon patients against 68.7% of 65 controls.Source 6 · Clinical trialWaon therapy improves the prognosis of patients with chronic heart failureKihara T, Miyata M, Fukudome T, et al.. Journal of Cardiology, 2009.Read the paper ↗PubMed ↗ That comparison wasn't randomized. Finnish-style saunas have barely been tested in heart failure: in one study, 12 men with chronic heart failure went through two 80°C sessions and a cold plunge, and none had complex heart rhythm problems.Source 7 · Clinical trialAcute effects of Finnish sauna and cold-water immersion on haemodynamic variables and autonomic nervous system activity in patients with heart failureRadtke T, Poerschke D, Wilhelm M, et al.. European Journal of Preventive Cardiology, 2016.Read the paper ↗PubMed ↗
The dial reads 48°H for four reasons
How the reading adds up
10 + 14 + 14 + 10 = 48°H
EvidenceWhat kind of evidence exists in people?
10/25Randomized trials exist, and the largest one enrolled 149 patients and missed its primary endpoint.Source 1 · Randomized trialWaon Therapy for Managing Chronic Heart Failure – Results From a Multicenter Prospective Randomized WAON-CHF Study –Tei C, Imamura T, Kinugawa K, et al.. Circulation Journal, 2016.Read the paper ↗PubMed ↗ Evidence on deaths and readmissions comes from a non-randomized comparison of 129 patients at one hospital.Source 6 · Clinical trialWaon therapy improves the prognosis of patients with chronic heart failureKihara T, Miyata M, Fukudome T, et al.. Journal of Cardiology, 2009.Read the paper ↗PubMed ↗
ConsistencyHas the finding held up?
14/25Most studies come from one Japanese research network, and none was blinded. A meta-analysis pooled a fall in BNP from five of them, while the largest trial found no difference in BNP against controls.Source 5 · Meta-analysisEffects of sauna bath on heart failure: A systematic review and meta‐analysisKällström M, Soveri I, Oldgren J, et al.. Clinical Cardiology, 2018.Read the paper ↗PubMed ↗Source 1 · Randomized trialWaon Therapy for Managing Chronic Heart Failure – Results From a Multicenter Prospective Randomized WAON-CHF Study –Tei C, Imamura T, Kinugawa K, et al.. Circulation Journal, 2016.Read the paper ↗PubMed ↗
MagnitudeDoes the claim match the size of the effect?
14/25After two weeks, Waon patients walked 44.9 meters farther in six minutes and controls 12.7 meters farther, while BNP and ejection fraction ended no different between the groups.Source 1 · Randomized trialWaon Therapy for Managing Chronic Heart Failure – Results From a Multicenter Prospective Randomized WAON-CHF Study –Tei C, Imamura T, Kinugawa K, et al.. Circulation Journal, 2016.Read the paper ↗PubMed ↗ The word treats implies a lasting effect on the disease, and no randomized trial has measured deaths or readmissions.
DoseDoes the studied protocol match how people use it?
10/25Patients spent 15 minutes in a 60°C far-infrared sauna and 30 minutes under a warm blanket five days a week in hospital, and they drank water afterward to replace what they sweated out.Source 1 · Randomized trialWaon Therapy for Managing Chronic Heart Failure – Results From a Multicenter Prospective Randomized WAON-CHF Study –Tei C, Imamura T, Kinugawa K, et al.. Circulation Journal, 2016.Read the paper ↗PubMed ↗ A session in a home cabin has none of that supervision.
The claim drifts from the data here
The largest randomized trial missed its main target. BNP fell within the Waon group, which is the figure that tends to get quoted, while the comparison with controls that the trial was built around showed no difference.Source 1 · Randomized trialWaon Therapy for Managing Chronic Heart Failure – Results From a Multicenter Prospective Randomized WAON-CHF Study –Tei C, Imamura T, Kinugawa K, et al.. Circulation Journal, 2016.Read the paper ↗PubMed ↗ A later subanalysis found BNP and two related hormones no different between the groups.Source 8 · Clinical trialNeurohumoral Modulation During Waon Therapy in Chronic Heart Failure ― Subanalysis of Waon-CHF Study ―Ichiki T, Burnett Jr JC, Scott CG, et al.. Circulation Journal, 2017.Read the paper ↗PubMed ↗
Two weeks of in-hospital sessions with weights checked before and after is a long way from a home infrared cabin. The survival data come from a study in which the Waon group had to keep coming back for sessions, and patients well enough to keep coming may have done better anyway.Source 6 · Clinical trialWaon therapy improves the prognosis of patients with chronic heart failureKihara T, Miyata M, Fukudome T, et al.. Journal of Cardiology, 2009.Read the paper ↗PubMed ↗
Put it to use
If you have heart failure, raise Waon with your cardiologist and keep taking your prescribed treatment, since the trials added it to unchanged heart medicines in hospitalized patients.Source 1 · Randomized trialWaon Therapy for Managing Chronic Heart Failure – Results From a Multicenter Prospective Randomized WAON-CHF Study –Tei C, Imamura T, Kinugawa K, et al.. Circulation Journal, 2016.Read the paper ↗PubMed ↗ Read what the studies say about saunas for heart patients for the conditions where experts advise against heat.
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People also ask
What is Waon therapy?
Waon is a Japanese protocol of 15 minutes in a far-infrared dry sauna held at 60°C, then 30 minutes of rest under a warm blanket. In trials, patients were weighed before and after, and they drank water to replace what they sweated out.Source 1 · Randomized trialWaon Therapy for Managing Chronic Heart Failure – Results From a Multicenter Prospective Randomized WAON-CHF Study –Tei C, Imamura T, Kinugawa K, et al.. Circulation Journal, 2016.Read the paper ↗PubMed ↗
Is infrared sauna safe for people with heart failure?
In the WAON-CHF trial, adverse events occurred in 22% of Waon patients and 15% of controls, and the difference wasn't significant. No one died during the trial. Seven events were linked to the therapy, among them two falls in blood pressure and two cases of low blood volume.Source 1 · Randomized trialWaon Therapy for Managing Chronic Heart Failure – Results From a Multicenter Prospective Randomized WAON-CHF Study –Tei C, Imamura T, Kinugawa K, et al.. Circulation Journal, 2016.Read the paper ↗PubMed ↗
Can a regular Finnish sauna help heart failure?
Almost nothing has tested it. A 2018 meta-analysis found only infrared Waon studies that met its criteria, and a small study of 12 men with heart failure found that two 80°C sessions caused no complex heart rhythm problems.Source 5 · Meta-analysisEffects of sauna bath on heart failure: A systematic review and meta‐analysisKällström M, Soveri I, Oldgren J, et al.. Clinical Cardiology, 2018.Read the paper ↗PubMed ↗Source 7 · Clinical trialAcute effects of Finnish sauna and cold-water immersion on haemodynamic variables and autonomic nervous system activity in patients with heart failureRadtke T, Poerschke D, Wilhelm M, et al.. European Journal of Preventive Cardiology, 2016.Read the paper ↗PubMed ↗
Check these claims next
53°H
Early
“Saunas are dangerous if you have heart disease.”
People with stable coronary disease or heart failure tolerated sauna sessions in small studies, and experts reserve the warning for specific conditions such as unstable chest pain or a recent heart attack. The reported sauna deaths mostly involved existing heart disease, often with alcohol.
83°H
Hot air
“Infrared saunas work better than traditional saunas.”
No trial has compared infrared and traditional saunas on any health outcome. In the one head-to-head physiology study, a typical infrared session left core temperature unchanged while a traditional sauna raised it 0.4°C.
36°H
Likely
“Using a sauna four to seven times a week halves your risk of dying from heart disease.”
In one Finnish cohort, men who took four to seven saunas a week died of heart disease at about half the rate of men who went once a week. Later analyses of the same men found a smaller gap, and the link was missing in the fittest men and in women who went two or three times a week.
We cited these sources
- 01Tei C, Imamura T, Kinugawa K, Inoue T, Masuyama T, Inoue H, et al.. Waon Therapy for Managing Chronic Heart Failure – Results From a Multicenter Prospective Randomized WAON-CHF Study –. Circulation Journal. 2016;80(4):827-834. doi:10.1253/circj.CJ-16-0051 PMID 27001189
- 02Tei C, Horikiri Y, Park JC, Jeong JW, Chang KS, Toyama Y, et al.. Acute Hemodynamic Improvement by Thermal Vasodilation in Congestive Heart Failure. Circulation. 1995;91(10):2582-2590. doi:10.1161/01.CIR.91.10.2582 PMID 7743620
- 03Kihara T, Biro S, Imamura M, Yoshifuku S, Takasaki K, Ikeda Y, et al.. Repeated sauna treatment improves vascular endothelial and cardiac function in patients with chronic heart failure. Journal of the American College of Cardiology. 2002;39(5):754-759. doi:10.1016/S0735-1097(01)01824-1 PMID 11869837
- 04Miyata M, Kihara T, Kubozono T, Ikeda Y, Shinsato T, Izumi T, et al.. Beneficial effects of Waon therapy on patients with chronic heart failure: Results of a prospective multicenter study. Journal of Cardiology. 2008;52(2):79-85. doi:10.1016/j.jjcc.2008.07.009 PMID 18922381
- 05Källström M, Soveri I, Oldgren J, Laukkanen J, Ichiki T, Tei C, et al.. Effects of sauna bath on heart failure: A systematic review and meta‐analysis. Clinical Cardiology. 2018;41(11):1491-1501. doi:10.1002/clc.23077 PMID 30239008
- 06Kihara T, Miyata M, Fukudome T, Ikeda Y, Shinsato T, Kubozono T, et al.. Waon therapy improves the prognosis of patients with chronic heart failure. Journal of Cardiology. 2009;53(2):214-218. doi:10.1016/j.jjcc.2008.11.005 PMID 19304125
- 07Radtke T, Poerschke D, Wilhelm M, Trachsel LD, Tschanz H, Matter F, et al.. Acute effects of Finnish sauna and cold-water immersion on haemodynamic variables and autonomic nervous system activity in patients with heart failure. European Journal of Preventive Cardiology. 2016;23(6):593-601. doi:10.1177/2047487315594506 PMID 26152773
- 08Ichiki T, Burnett Jr JC, Scott CG, Heublein DM, Miyata M, Kinugawa K, et al.. Neurohumoral Modulation During Waon Therapy in Chronic Heart Failure ― Subanalysis of Waon-CHF Study ―. Circulation Journal. 2017;81(5):709-716. doi:10.1253/circj.CJ-16-1117 PMID 28202884