In the mountainous regions of Europe, there are volcanic areas that emit carbon dioxide gas.
The ancient Romans began using these springs for bathing and also started utilizing the water for drinking.

The film “Thermae Romae” depicts how the ancient Romans used hot springs for treating wounds and illnesses. Among these, Germany has been particularly active in research, and due to its gentle effects on the heart, carbonated springs there are known as the “heart’s bath” and have been used for spa treatments for a long time.

In Japan, Western hot spring medicine is said to have been introduced in the late Edo period.
Research progressed in the early Showa era by researchers who studied balneotherapy in Germany.
However, natural carbonated springs are scarce in Japan, making them valuable.

Bathing in carbonated springs is said to warm the body from the core, promoting blood circulation and relieving coldness, shoulder stiffness, lower back pain, and muscle pain. One of the few bicarbonate springs in Japan is Nagayu Onsen in Oita Prefecture. Despite its low temperature, it is famous for its ability to warm the body from the core with prolonged bathing.

 

About Natural Carbonated Springs

Natural carbonated springs have been used for therapeutic purposes for a long time. They are expected to improve blood flow and boost immunity without burdening the body.

However, the carbon dioxide gas in these springs, which is believed to play a key role, is barely absorbed through the skin and quickly evaporates into the air.

So, what is the true effect of these springs?

 

The True Effect of Natural Carbonated Springs

Many renowned carbonated springs share a common characteristic: the pH of the natural carbonated spring and the presence of bicarbonate ions dissolved in the water.

Generally, carbonated springs are defined as having over 1000 ppm of dissolved carbon dioxide gas in acidic water, which is nearly a supersaturated state.

However, famous therapeutic springs in Germany and Nagayu Onsen in Oita Prefecture have nearly neutral pH levels (6.7-7.1), which cannot retain large amounts of carbon dioxide gas. Instead,
the carbon dioxide transforms into bicarbonate ions that remain in the water. These bicarbonate ions are considered to be the main effective component.