The treatment is a lot cooler than a traditional steam sauna that reaches about 176 degrees Fahrenheit.
Under medical supervision, the patient lies on a bench in a 140 degree Fahrenheit, infrared dry sauna for 15 minutes. Infrared saunas use a special heater that generates infrared radiation similar to that produced by the sun.
Then, the patient is bundled in blankets to keep warm while resting on a bed outside the sauna for 30 minutes. Water is given throughout the process to maintain hydration.
The study involved patients taking standard medications for heart failure. Half were randomly assigned to receive Waon treatments at least twice a week.
Over the next five years, 31.3% of those given Waon therapy had to be rehospitalized for heart failure or died of heart disease vs. 68.7% in the non-Waon therapy group.
Waon therapy is not available in the U.S., according to Yoshiyuki Ikeda, MD. Ikeda, a fellow in the department of cardiovascular, respiratory and metabolic medicine at Kagoshima University in Kagoshima, Japan, led the study. He reported the findings at the annual meeting of the American College of Cardiology.
Waon Therapy Relaxes Blood Vessels
Heart failure happens when the heart's weak pumping action causes a buildup of fluid in the lungs and other body tissues. The major cause of heart failure is a heart attack or coronary artery disease, according to the American Heart Association (AHA).
The warm sauna helps blood vessels to relax, facilitating the flow of blood from the heart to other organs throughout the body, Ikeda says.
"That's what many of the heart medications do," he tells WebMD.
Previous research has shown that Waon therapy can also help correct irregular heart rhythms and improve heart disease symptoms, Ikeda says.
AHA spokesman Russell Luepker, MD, of the University of Minnesota, says that he's not convinced the warm treatments made the patients better.
"They were being seen twice weekly for the treatment, and everyone feels better when they get more attention. Plus, they may have received additional medical care during the visits," he tells WebMD.
The AHA has no official position on Waon therapy. But people with symptoms of heart disease such as chest pain or shortness of breath, as well as those with high blood pressure, should avoid a hot tub or sauna, the AHA says.
"Sitting too long in a hot bath makes a stressed heart work harder," Ikeda says. "Waon therapy involves a much lower temperature than traditional sauna and close medical supervision."