The claim
“Infrared sauna therapy treats heart failure.”
Unsettled. In the largest randomized trial, two weeks of Waon therapy (a 60°C infrared sauna followed by rest under a warm blanket) helped heart-failure patients walk farther. 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
A little human data and a plausible mechanism support it. Better trials have to come before anyone relies 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. It also lowered the pressure inside the heart as it filled, and the heart pumped better afterward.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 ↗
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 their arteries widened better 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 study of 188 patients at several hospitals found that BNP fell from 542 to 394 pg/mL with Waon. 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 ↗
The largest test was the WAON-CHF trial. At 19 Japanese hospitals, 149 patients with advanced heart failure were randomly assigned 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 trial was built to compare the change in BNP between the groups, and that comparison showed no difference (P = 0.4179). In a six-minute walk, the Waon group went 44.9 meters farther than before and the controls 12.7 meters farther. Heart size on chest X-ray shrank a little more with Waon.
A 2018 analysis pooled seven Waon studies with 491 patients, and Waon's developer was one of its authors. Over two to four weeks, it found lower BNP and a 1.45-point rise in ejection fraction (the share of blood the heart pumps out with each beat).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, so patients knew whether they were getting Waon. Eight of the nine it reviewed came from Japan.
Survival data come from one hospital. After five years, 31.3% of the 64 Waon patients had been readmitted for heart failure or died of a heart-related cause. Among the 65 controls, 68.7% had.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 human evidence exists?
10/25Randomized trials exist. The largest enrolled 149 patients and fell short on its main measure.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 129 patients at one hospital who weren't randomized.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 ↗
ConsistencyHave other studies found the same thing?
14/25Most studies come from one Japanese research network, and none was blinded. A pooled analysis found BNP fell across five of them. The largest trial found no difference in BNP compared with 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. BNP and ejection fraction ended up 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 deaths and readmissions have only been tracked outside randomized trials.
DoseDoes the studied dose match how people use it?
10/25Five days a week in hospital, patients spent 15 minutes in a 60°C far-infrared sauna and then 30 minutes under a warm blanket. Afterward they drank water to replace what they had 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. People tend to quote the fall in BNP within the Waon group. The comparison with controls, which 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 look at the same trial's data 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 hospital sessions, with patients weighed before and after, is a long way from a home infrared cabin. The survival data come from a study where the Waon group had to keep coming back for sessions. 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. The trials added Waon 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.
From our sister magazine
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People also ask
What is Waon therapy?
Waon is a Japanese heat treatment. Patients spend 15 minutes in a far-infrared dry sauna held at 60°C and then rest under a warm blanket for 30 minutes. In trials, they were weighed before and after and 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 largest trial, which ran in hospital, Waon patients didn't have significantly more health problems than controls, and no one died. Adverse events hit 22% of the Waon group and 15% of controls. Seven were linked to the therapy, and they included 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?
Researchers have barely looked. A 2018 pooled analysis found only infrared Waon studies that met its criteria. 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
Unsettled
“Saunas are dangerous if you have heart disease.”
People with stable coronary disease or heart failure tolerated sauna sessions in small studies. Experts save the warning for specific conditions such as unstable chest pain or a recent heart attack. Most of the reported sauna deaths involved people who already had heart disease, and alcohol often played a part.
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 a Finnish study that tracked men for about 20 years, those who took four to seven saunas a week died of heart disease at about half the rate of once-a-week bathers. Later analyses of the same men found a smaller difference. The link didn't show up in the fittest men, and women who went two or three times a week did no better than women who went once.
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