Explanations by Spring Quality

"Hot spring for heart" with vasodilating effect by carbon dioxide gas

Hot springs with more than 1,000 mg of free carbon dioxide (free carbonic acid)（CO₂）in 1 kg of hot spring water.
The temperature of the spring is often low, and when you bathe in it, you feel carbon dioxide bubbles on your body, which is a refreshing sensation. It is called “Hot springs with bubbles”. However, if the temperature of the spring is high or the water is heated, the carbon dioxide gas may volatilize.
When you bathe in a "Carbon dioxide springs" with a temperature of around 35℃, you will feel cool at first, but as soon as bubbles begin to form on your skin, you will notice that your body is slowly warming up.
This is because carbon dioxide (gas) is absorbed into the skin and dilates blood vessels, thus improving blood circulation. Therefore, it is called a “Hot springs for heart” because it promotes blood circulation without stressing the heart. This blood circulation promoting effect has a speeding up of the treating process of Cuts. This is because carbon dioxide is absorbed through the skin, improving blood flow around the wound and stimulating cell regeneration in the skin. Also, because blood vessels dilate, blood pressure is lowered during bathing, and furthermore, as blood circulation improves, it relieves muscle and joint pain. At the same time, the increased relaxation effect helps to calm the autonomic nervous system, and the warm bath effect and blood circulation helps to relieve physical and mental tension, reduce stress and have an effect on Autonomic instability. Furthermore, the absorption of carbon dioxide through the skin and the dilatation of blood vessels contributes to improved blood flow in peripheral blood vessels. This in turn relieves symptoms of Sensitivity to cold and Peripheral circulatory disturbances. When drinking “Carbon dioxide spring water”, you can enjoy the refreshing carbonic acid throat sensation. It also stimulates the gastrointestinal tract, promotes digestion and helps to reduce Gastrointestinal hypofunction. This is because carbon dioxide stimulates the gastrointestinal tract lightly and helps the secretion of digestive enzymes, thereby improving gastrointestinal functions.
If you want to experience a “Carbon dioxide springs” that feels like bubbles sticking to your body, you must choose the "free-flowing spring water" method. The spring is also visually pleasing, but since the temperature is often low, it is more popular during the warmer seasons. However, taking a long bath in winter is not to be dismissed. Even if you take a long soak in a hot spring (42℃ or higher), many people limit themselves to 3 minutes even if they take a bath in a “rich” hot spring, which is called a “famous hot spring”. In this case, taking a prolonged “lukewarm” bath, which does not put a stress on the heart, is also an effective way to take a hot spring bath.
“Carbon dioxide springs” are numerous in Europe, where there are many old volcanic belts. In particular, “drinking springs” have become very popular. In Japan, where there are many active volcanic zones and newer volcanic zones, this type of spring is rare. Along with “Iron containing springs”, “Iodine containing springs”, and “Radioactive springs”, this type of spring is one of the rarest types of springs in Japan.

• ■Old spring name・・・Carbonic acid springs
• ■Color of water・・・Clear and colorless
• ■Taste & Smell・・・Sugar-free mineral carbonated water, odorless and tasteless, but may have a slight sour taste
• ■Water texture・・・In the case of bubbling spring temperatures, the water feels cool at first, but gradually becomes warmer
• ■Major hot spring inns・・・"Marucho Ryokan" Nagayu Onsen, Oita Prefecture／"Daimaru Ryokan" Nagayu Onsen, Oita Prefecture／"Wasurenosato Gajyoen" Myoken Onsen, Kagoshima Prefecture
List of inns with this spring quality