Explanations by Spring Quality

Skin keratin-softening "Hot spring for beauty" / Refreshing after bathing

Hot springs with more than 1,000 mg of dissolved substances (excluding gaseous substances) in 1 kg of hot spring water and with hydrogen carbonate ion（HCO₃^-）as the main anionic component.
The indications for bathing in hydrogen carbonate springs are Cuts, Peripheral circulatory disturbance, Sensitivity to cold, and Dry skin.
The indications for drinking by spring quality are Gastroduodenal ulcers, Reflux esophagitis, Impaired glucose tolerance (diabetes), Hyperuricemia (gout).
Hydrogen carbonate springs are classified according to the main component of cations as follows.

（1）Calcium (Magnesium) - Hydrogen carbonate spring (old name: sodium bicarbonate spring)
In many cases, it contains carbon dioxide and iron. The presence of earth elements such as calcium and magnesium also provides sedative and anti-inflammatory effects, and is good for allergic diseases, chronic skin diseases, and hives.
When drunk, it lowers blood glucose levels and is good for impaired glucose tolerance (diabetes). It is also effective for hyperuricemia (gout) and urinary tract stones, as it promotes the excretion of uric acid as well as diuresis. In addition, it neutralizes stomach acid, activates the stomach, and is good for chronic gastrointestinal disorders. Inhalation therapy using the spring's anti-inflammatory properties is also popular. This spring sometimes produces calcareous hot spring sediments and precipitates. This can often be seen at the entrance to the hot spring and at the edges of the bathtub.

（2）Sodium - Hydrogen carbonate spring (old name: sodium spring)
The pH value has a high probability of being alkaline and often contains sodium-chloride or sodium-sulfate. Sodium hydrogen carbonate, or sodium is stimulates blood circulation and softens dead skin cells (emulsification phenomenon).
And it is called "Hot water for beauty" because it is expected to have a cleansing effect that removes sebum and dirt like soap and makes the skin smooth.
Furthermore, the skin's protective power is weakened due to the reduced amount of sebum, which makes it easier for moisture on the skin surface to evaporate, also known as "Hot spring for refreshing".
Also, although the spring water tends to dry out and cool down easily after bathing, the hydrogen carbonate hydrolyzes keratin and sebum at high temperatures, producing hydrogen and carbon dioxide gases, which have a sterilizing and metabolism-promoting effect.
Therefore, the indications for bathing in this spring include Cuts, Peripheral circulatory disturbance, Sensitivity to cold, and Dry skin.
When drunk, the spring neutralizes gastric acid and produces carbon dioxide gas that stimulates the gastric mucosa, making it active and aiding digestion. That is why gastroduodenal ulcers and reflux esophagitis are among the spring-specific indications for drinking.
It is also good for cholelithiasis, chronic cholecystitis, and diabetes because it stimulates the secretion of liver juices and improves the function of the liver and pancreas.
In Europe, it is popularly used as a "Hot spring for liver" drinking therapy.
Inhalation therapy is also popular, and is often used for chronic inflammation of the upper respiratory tract and chronic obstructive respiratory disease with difficulty in expectorating, utilizing the buffering effect of baking soda and its ability to dissolve mucous membranes in the airways.
Note that a "Hydrogen carbonate spring" in which the main anionic component is hydrogen carbonate ion（HCO₃^-）is different from a "Carbon dioxide spring" (old name: carbonic acid spring) in which bubbles form on the skin and the free carbon dioxide（CO₂）content is above the standard value. The indications are also different, with some exceptions.

• ■Old spring name・・・Sodium bicarbonate spring／Sodium spring
• ■Color of water・・・Clear and colorless, but sometimes yellowish brown or greenish brown
• ■Taste & Smell・・・
  「Calcium (Magnesium) - Hydrogen carbonate spring」May have a bitter, metallic or medicinal odor
  「Sodium - Hydrogen carbonate spring」Has a medicinal taste characteristic of baking soda, but is easy to drink; may have a metallic or medicinal odor。
• ■Water texture・・・Smooth feeling
• ■Major hot spring inns・・・
  「Sodium - Hydrogen carbonate spring」"Ryokan Onuma" Higashi-Naruko Onsen, Miyagi Prefecture
  「Carbon dioxide containing－Magnesium・Sodium・Calcium－Hydrogen carbonate spring」"Marucho Ryokan" Nagayu Onsen, Oita Prefecture
  「Sodium・Calcium・Magnesium－Hydrogen carbonate spring」"Wasurenosato Gajyoen" Myoken Onsen, Kagoshima Prefecture
List of inns with this spring quality