New research suggests that taking hot baths, soaking in hot tubs or using saunas can prevent cardiovascular diseases such as heart disease, high blood pressure and Type 2 diabetes.
The research was presented last week at the Annual Meeting of the European Association for the Study of Diabetes (EASD), held virtually this year.
Hisayuki Katsuyama, co-author of the new study, is a physician at Kohnodai Hospital in Ichikawa, Japan. He says that while drug treatments have helped people with Type 2 diabetes live better, longer lives, daily habits such as diet and exercise are still important for these patients.
Katsuyama says he and his colleagues looked at previous research suggesting heat therapy, such as baths, hot tubs or saunas, can lower risks of fatal heart disease and stroke, along with having a lower body fat percentage, and thought it could be promising as a Type 2 diabetes treatment.
To test the theory, the researchers recruited 1,297 patients with Type 2 diabetes who regularly visited an outpatient hospital unit in Ichikawa between October 2018 and March 2019. They documented their bathing habits and noted water temperature, frequency and duration of each session, as well as a variety of medical notes.
Across the board, people who bathed more often had lower body mass indexes (BMI), diastolic blood pressure and glycated hemoglobin, a key risk factor for Type 2 diabetes.
In their presentation, the researchers say their findings suggest daily heat exposure by hot tub bathing can "contribute to improvements of glycemia, hypertension and obesity, and thus, can be a therapeutic option for patients with Type 2 diabetes."
In an interview, Katsuyama says he suspects patients may benefit from heat therapy in a way similar to the benefit they get from exercise. He says both seem to improve insulin sensitivity and enhance energy expenditure.
Other research suggests bathing increases blood circulation, body temperature and the production of nitric oxide in the body, which appears to confer the positive benefits. Katsuyama says more research is needed before more conclusions can be made.
The study has not yet been published or peer reviewed.