Waon therapy improved walking distance in heart failure and missed its main target
In this 2016 Circulation Journal trial, 19 Japanese hospitals randomly assigned 149 heart-failure patients to two weeks of Waon therapy (a warm infrared sauna) or to standard care alone.
The paper
Waon Therapy for Managing Chronic Heart Failure – Results From a Multicenter Prospective Randomized WAON-CHF Study –
Tei C, Imamura T, Kinugawa K, Inoue T, et al.. Circulation Journal, 2016;80(4):827-834.
See the study at a glance
- Design
- Randomized controlled trial (open label)
- People
- 149 patients
- Who they were
- The patients were in hospital with advanced heart failure. Their average age was 66, 61% were men, and their BNP (a blood marker of heart strain) stayed above 300 pg/mL after at least a week of treatment.
- What they did
- Patients sat for 15 minutes in a far-infrared dry sauna held at 60°C and then rested under a warm blanket for 30 minutes. They did this five days a week for two weeks. Weight was checked before and after each session, and heart-failure drug doses stayed fixed.
- How long
- 2 weeks (10 sessions)
These numbers came out of it
P = 0.4179
BNP was the trial's main measure, and it changed no differently with Waon than with standard care.
+44.9 m
Waon patients walked this much farther in six minutes by the end, and controls gained 12.7 m.
22%
This share of Waon patients had at least one adverse event. Among controls it was 15%, and the difference wasn't significant.
0
No patient in either group died during the trial.
The researchers did this
WAON-CHF was the largest randomized test of Waon therapy. Nineteen Japanese hospitals enrolled patients admitted with advanced heart failure whose BNP was above 500 pg/mL on admission and still above 300 after at least a week of treatment.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 ↗ Of 153 patients enrolled, 149 were randomized. Seventy-six got Waon, and 73 got the same care without it.
Five days a week for two weeks, Waon patients sat in a 60°C far-infrared sauna for 15 minutes and then lay under a warm blanket for 30. They were weighed before and after and drank water to replace their sweat, and their drug doses were held steady.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 groups. BNP fell within the Waon group, and the difference from controls was not significant (P = 0.4179).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 ↗ Six-minute walking distance rose by 44.9 meters with Waon and by 12.7 meters in controls, and on chest X-ray the heart shrank a little more with Waon. Physicians who knew the assignments graded symptom class (how much the illness limited each patient), and it improved more with Waon. Ejection fraction (the share of blood the heart pumps out with each beat) and blood pressure ended up similar.
Adverse events occurred in 22% of Waon patients and 15% of controls, and the difference wasn't significant. Seven events were tied to Waon. They included two falls in blood pressure and two cases of low blood volume. One Waon patient had an episode of atrial fibrillation, and nobody died.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 no difference between groups in BNP or two related hormones, and improvements showed up only in subgroups picked after the fact.Source 2 · 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 ↗ The trial's authors suggested that people with advanced heart failure may need 20 to 40 sessions.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 study can't tell you these things
- The trial was open label, so the physicians who graded symptom class knew who got Waon.
- Two weeks of sessions in hospital can't show effects on survival or readmission.
- The groups differed at the start in body mass index and diabetes.
- A supervised 60°C infrared sauna followed by blanket rest is a different thing from a home cabin or a Finnish sauna.
People quote it like this
Waon is often described as improving heart function. A pooled analysis that included this trial concluded that sauna brings short-term improvement in cardiac function.Source 3 · 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 ↗ The heart marker this trial picked in advance showed no difference from standard care.
From our sister magazine
Sauna Monthly explains how infrared cabins differ from traditional saunas
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
- 02Ichiki 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
- 03Källström 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