Reference
Sobajima M, Nozawa T, Fukui Y, et al. Waon therapy improves quality of life as well as cardiac function and exercise capacity in patients with chronic heart failure. Int Heart J. 2015;56(2):203-208.
Design
Prospective cohort pilot study
Participants
Forty-nine hospitalized patients who were consecutively enrolled at Toyama University Hospital, Japan, during an unspecified timeframe were recruited according to eligibility criteria of chronic heart failure (CHF). Participants classified as belonging to the New York Heart Association (NYHA) functional class II or above were included. Even if they had been previously hospitalized for heart failure, all participants included in the study were deemed to be in a stable condition and were not receiving any intravenous medication at the time of enrollment. No medication was changed during the study period for any study participants.
Twenty patients had ischemic cardiomyopathy, and 29 patients had nonischemic cardiomyopathy. More than 60% of the patients were treated with beta-blockers and 86% with angiotensin converting enzyme inhibitors or angiotensin receptor blockers.
Intervention
Waon therapy (WT) was administered daily for 3 weeks. WT is a hyperthermic treatment wherein patients sit for 15 minutes in a 60-degree C (140-degree F) far-infrared sauna followed by 30 minutes of lying supine covered in warm blankets sufficient to raise the body temperature 1.0 to 1.2 degrees C. Oral hydration was given during and after the therapy.
Outcome Measures
Measured were heart rate, blood pressure, body weight, NYHA class, specific activity scale (SAS), 6-minute walk distance (6MWD) test, left ventricular ejection fraction (LVEF), left ventricular end systolic and diastolic measurements, left atrial dimension, blood urea nitrogen, creatinine, high-density lipoprotein and low-density lipoprotein cholesterol, triglycerides, blood sugar, B type/brain natriuretic peptide (BNP), plasma norepinephrine, natural killer (NK) cells, flow mediated dilation (FMD), and quality of life (QOL) using the Short Form Health Survey-36 (SF-36) questionnaire.
Key Findings
No patient exhibited a worsening of clinical symptoms or suffered from complications due to WT, and there were no reported adverse events. WT significantly improved NYHA functional class, SAS, and 6MWD, which are markers for activity level and exercise tolerance. LVEF and NK cell activity were slightly but significantly increased, and plasma levels of BNP were reduced after WT. WT improved vascular endothelial function assessed by FMD. Standard cardiac measurements were obtained using echocardiography.
The authors note that CHF patients had lower QOL scores in all components of SF-36 compared to the average scores of the general population of Japan. Three weeks of WT significantly improved physical components and mental components of the SF-36, especially in the nonischemic group. Among the study’s limitations were that its long-term effects remain undetermined, the study sample was small, and there were no randomization, blinding, or control procedures used.
Practice Implications
Although previous studies suggested caution with sauna bathing regarding cardiovascular health,1 new data have accumulated suggesting sauna may benefit patients with CHF. A recent prospective cohort study of 2,315 men conducted by a Finnish group of heart doctors and researchers concluded that after a median follow-up of 20.7 years, sauna bathing was inversely associated with the risk of fatal cardiovascular (sudden cardiac death, coronary heart disease [CHD], cardiovascular disease [CVD]) and all-cause mortality events2 independent of conventional risk factors. Specifically, it was shown that men who enjoyed sauna 2 to 3 times per week had a 23% lower risk of experiencing a fatal episode of CHD or CVD compared with men having 1 sauna per week. Men who used the sauna 4 to 7 times per week had a 48% lower risk. In this study, participants were divided into groups on the basis of the frequency of sauna bathing (once/wk, 2-3 times/wk, or 4-7 times/wk) and according to the typical duration of sessions (less than 11 min, 11-19 min, or more than 20 min).
While many hospitals have cardiac rehabilitation centers that include physical and occupational therapies, few if any hospitals have far-infrared saunas.
Sauna can increase heart rate during sessions corresponding to moderate-intensity physical exercise.3,4 Sauna use has also demonstrated temporal increased cardiac output and heart rate in subjects.4-8 Sweat secretion has been reported to occur at a known rate during sauna treatments and is often cited as a rationale for promoting specific oral hydration regimens.5,9,10 Recent studies tell us that repeated sauna treatment is safe for CHF patients and that it can specifically improve endothelial function, exercise tolerance, and ejection fraction.11,12 Specifically, data on WT show benefits in CHF patients worth noting.8,11-14
Results from this pilot study suggest that WT is safe and may have mental and physical benefits for CHF patients. Specifically, the results showing improvement in overall QOL in addition to improvement in cardiac and vascular endothelial function and exercise tolerance are encouraging. While many hospitals have cardiac rehabilitation centers that include physical and occupational therapies, few if any hospitals have far-infrared saunas. Given the wealth of studies, some patients may be interested in purchasing far-infrared saunas for home use. It is our responsibility to counsel these patients on safety issues regarding sauna therapy, especially if they have CHF or any other chronic condition. Education about oral hydration and limiting time spent during each session, as well as recommending safety measures such as session timers, would be a start.
