Technically speaking, a hot spring is a spring produced from the emergence of geothermally heated groundwater from the earth's crust, and its temperature is approximately 5oC higher than its surroundings. Yet the standard temperature of hot spring varies across the globe, with 30oC or above being the temperature requirement defined by the Hot Spring Law of Taiwan, 25oC by equivalent legislation in Japan and Korea, and 20oC or 70oF by that in Europe and the United States. In Japan and Taiwan, even the quality of and minerals in the hot spring water are stringently regulated. Before you go on a trip to the hot springs around the world, it's wise to learn about the different types of hot springs in the world, and what you need to know about the etiquettes and health issues before taking a dip.

Types of Hot Springs and Therapeutic Benefits

Rich in minerals and boasting a plethora of health benefits, hot spring has historically been regarded as a precious gift of the nature. Hot spring in China was mentioned as early as the Northern Wei period of China, in the ancient Chinese geographical literature by Li Dao-yuan in his Shuijingzhu, or 'The River Classic': "The water of the Huang Nu hot spring in Lushan county cooks rice and cures diseases. By cleansing their bodies with the water three times a day for 40 days, the Taoists can have their diseases cured." Additionally, in the Hot Spring Inscription penned by Emperor Taizong of Tang in his late years, the Emperor also expressed his hope of treating the diseases he was suffering through a dip in the hot spring, which goes on to show how hot spring was celebrated for its plentiful health benefits from ancient times to now. Find out more about the different types of hot spring according to their mineral content, and their health benefits below:

• Simple spring – Known for its mild, gentle and low-stimulation qualities, the simple spring's water is usually around 25oC or above, and is colourless and odourless. With health benefits such as blood circulation enhancement and overall self-heal ability, this hot spring is suitable for senior citizens.

• Sodium bicarbonate saline spring – Depending on its sodium bicarbonate content, this type of hot spring can be further classified into sodium bicarbonate and bicarbonate earth hot springs. But both types of saline hot springs are effective in skincare and warming the body while improving gynaecological diseases and diabetes. When treated into drinking water, the water of this type of hot spring can cure gastro diseases, which is why it is also called the 'hot spring for the stomach and intestines'.

• Sulphur spring – Known for its odour that is similar to rotten eggs, this type of hot spring can soften the dead skin, alleviate itchiness, detoxify, as well as soothe chronic skin diseases and respiratory diseases.

• Alkaline spring – Known as the hot spring for beauty, this type of hot spring water measures about 58oC as it rises to the surface. The water is rich in minerals the likes of sodium, magnesium, calcium, potassium, and hydrogen carbonate ions, and it is clear and odourless, with a pH value of 7, making it a great solution for smooth and softer skin, improved skin quality, and alleviation of inflammation and scars. The alkaline hot spring is widely reputed as the hot spring of hot springs.

• Carbon dioxide spring – With a temperature lower than average, the water of this type of hot spring can temporarily expand the capillaries, lower blood pressure and enhance blood circulation. It is also called the 'hot spring for the heart' because it doesn't cause a rapid increase in pulse rate. The bubbles that form on the skin surface because of the carbon dioxide content in the water have mild massage functions, and this is also why this type of hot spring is also referred to as the 'bubbly spa'.

Thanks to the earth's active plate tectonics, hot springs can be found anywhere in the world. Kurhaus ('cure house') is a type of spa originated in Europe, where chronic diseases are alleviated through the inhalation and drinking of the water, and spa treatments. Autumn and winter are the seasons when a dip in the hot spring beckons with the temptation to enjoy the temperature differences between the hot and cold, as well as the therapeutic benefits of the hot spring water Continue to read the next article for a few hot spring recommendations you may want to have a think about if you're planning for a trip abroad!

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Take a Dip Around the World (2)