Research: Japanese Hot Spring Baths Effective in Treating Multiple Diseases

The Umi Jigoku, or Sea Shell Hotspring in the city of Beppu Japan. (Promotion Airport Environment Improvement Foundation/JNTO)

Japanese people have a long history of bathing in hot springs to cure diseases. Soaking in a hot spring not only helps people reduce stress but also boasts many beauty and health benefits. Evening hot spring bathing can even improve sleep disorders and prevent high blood pressure, according to new research.

Soaking in hot springs after 7 p.m. can reduce the incidence of high blood pressure in people over the age of 65, according to the Nov. 30 announcement of a research team led by Dr. Yamazaki Satoshi of the Department of Endocrine and Metabolic Diseases at Kyushu University Hospital in Japan.

More than 60 percent of Japanese over the age of 50 suffer from high blood pressure, according to Japan’s Health Ministry.

The research team surveyed 10,000 people aged 65 or older in Beppu City, Oira Prefecture, Japan, starting in 2011. The researchers analyzed the subjects’ age, sex, and history of diseases including depression, ischemic heart disease, arrhythmia, hypertension, stroke, gout, asthma, diabetes, hyperlipidemia, kidney disease, chronic hepatitis and more. Their habits of hot spring bathing were also analyzed, including frequency, soaking time, bathing years, and type of hot spring.

The entrance to the traditional Takegawara Hot Springs bathhouse in Beppu, Japan. (Promotion Airport Environment Improvement Foundation/JNTO)

The results showed that the low prevalence of hypertension in these elderly people is directly related to the fact that they take a hot spring bath at night (7 p.m.–11 p.m.). The analysis showed that hot springs in the evening not only helped reduce the incidence of chronic liver damage and high blood pressure but also improved sleep disorders caused by chronic stress.

According to the study, hot spring baths cause the human body to react to the increase in temperature, which changes the body’s secretion of hormones. Long-term hot spring baths can give the body a better resistance to stress.

The study was published in the Scientific Reports on Nov. 14.

Traditional Hot Spring Therapy

Hot spring therapy was practiced in Japan during the Nara period (710–794), as documented in ancient texts such as Nihon Shoki (Chronicle of Japan) and Otoji.

Known as “Tang Zhi”(meaning medicine bath treatment) in Japan, hot spring therapy refers to bathing in hot springs or medicinal baths, or sweating in stone baths (steam baths), using the effect of hot springs to cure diseases.

In 1948, the Japanese government introduced the Hot Spring Act, which stipulates that a spring can be called a natural hot spring only if the temperature of hot water gushing out of the ground is above 25 degrees C, the water or steam contains one of 19 substances such as iron, hydrogen ions, and sulfur ore, and the spring contains more than one gram of substances per kilogram.

Steam rises from hot spring bathhouses in Beppu, Japan. (Sean Pavone/Shutterstock)

According to Onsen Medical Science Research Center, the benefits of hot springs vary depending on their ingredients. Hot springs are divided into 10 types, according to their water quality: pure hot springs, carbonic acid springs, bicarbonate springs, sulphate springs, iron springs, iodine springs, salt springs, acid springs, radioactive springs, and sulfur springs.

Different springs target different diseases. According to the classification by the Center, carbonic acid springs have a certain effect on the prevention and treatment of heart disease, hypertension, and arteriosclerosis; bicarbonate springs moisturize the skin and soften the cuticles; sulphate springs can relieve chronic skin diseases; salt springs can improve cold hands and feet, anemia, and allergic bronchitis symptoms.

Iron-containing springs are colorless and transparent when they first emerge. After contact with oxygen, they become tea-brown and their effectiveness decreases. They are effective in treating anemia, rheumatism, menopausal disorders, uterine failure, and chronic eczema. Pure hot springs, which have various ingredients, can promote blood circulation and have a certain soothing effect on stroke and peripheral neuralgia; Sulfate springs can prevent arteriosclerosis and has a sedative effect.

Hot springs not only regulate the body but also relax the mind. There are many open-air hot springs where you can enjoy cherry blossoms in the spring, maples in the autumn, and snow in the winter. When soaking in hot springs, man and nature are perfectly integrated and the body and mind are well relaxed.