Hot springs are known around the world as centers of healing and rejuvenation. Yet despite their global abundance, no two hot springs are the same. Every natural thermal pool in the world boasts its own unique composition and mineral concentrations which differentiate it much like a human’s fingerprint.
However, despite the wide variability of these thermal pools, most hot springs can be collected into groups of similar compositions, including mineral contents and temperatures.
While the definition of a thermal pool and the different varieties are debated, these are the different types of hot springs that are most generally accepted.
The Different Types Of Hot Springs
Types of Hot Springs by Temperature
Since there is no universally accepted definition or required temperature for a hot spring, thermal pools can come in a wide range of degrees.
For example, according to World of Phenomena, the most generally accepted definition of a hot spring is any natural spring with an average temperature slightly warmer than the human body, at around 98 degrees. However, others argue that a hot spring is any natural spring with water temperatures sustainability higher than its surrounding environment.
Since these varying definitions of the term result in a massive range of what can be considered appropriate temperatures for a hot spring, the first method many individuals use to classify different types of hot springs is according to the following categories based on their average temperatures.
- Cold Spring (less than 65° F)
- Warm Spring (65-98° F)
- Hot Spring (98-122° F)
- High Temp Hot Spring (122° F+)
The Different Types of Hot Springs by Mineral Composition
Beyond their heat, hot springs are also classified according to their mineral compositions. Since water can hold more dissolved solids the warmer it is heated, hot springs boast much higher mineral concentrations than their cold-water alternatives.
Hot springs collect their abundant minerals as a result of the geothermal processes of heating. During this time, the water passes through the earth’s surface, absorbing the minerals from the surrounding rocks. As a result, every hot spring boasts its unique mineral content that provides for varying soaking experiences with diverse pH values and health benefits.
While each hot spring boasts a unique chemical composition, most thermal pools can be classified according to these ten specific varieties. However, a pool can also exist as a combination of these types.
As the name suggests, a simple hot spring is the most basic variety of thermal pools, which boasts lower concentrations of minerals than other springs. However, these lower mineral concentrations offer a soothing soaking experience perfect for children and the elderly.
According to Japan-Guide.com, simple hot springs alleviate various ailments, including fatigue, nerve pain, insomnia, and high blood pressure.
Reflective of seawater, a chloride fountain’s primary mineral is sodium chloride, commonly known as salt. However, while sodium is the most abundant chemical combined with chloride in hot springs, other combined chemicals can include potassium, lithium, calcium, magnesium, and iron.
Due to their high mineral contents, chloride fountains are known for numerous health benefits, including alleviating the symptoms of skin conditions, muscle and joint pain, cuts, burns, and more.
Easily recognizable by its potent rotten egg smell, the sulfur spring is one of the most abundant varieties of thermal pools in the world. Known to boast curative soaks since ancient times, the waters of a sulfur spring function to expand blood vessels while softening the skin.
As a result, sulfur hot springs are famous for their ability to treat acne, skin spots, cuts, diabetes, high blood pressure, and joint pain. However, spring-goers should be cautious when engaging in a sulfur spring, as the chemical composition is known to trigger allergic reactions in some individuals.
Additionally, spring-goers should refrain from swimming in any unknown wild hot springs with a rotten egg-like smell as hydrogen sulfide is known to boast toxic effects in high concentrations and can be fatal to unknowing soakers, according to Dhiefa.
Sulfate springs are further broken down into sodium sulfate, calcium sulfate, or magnesium sulfate hot springs. All three of these thermal pool varieties are known for their healing abilities. They have even been nicknamed the “scratchy hot waters” thanks to their ability to facilitate the healing of cuts, burns, and skin diseases.
Additionally, these mineral pools are known to also boast a sedative and blood pressure lowering effect, along with the ability to relieve constipation when ingested.
According to the National Park Service’s Analyses of the Waters of The Hot Springs of Arkansas, carbonate-rich alkaline waters are some of the most important mineral waters in the world. Combined with sodium, potassium, lithium, magnesium, calcium, or iron in hot springs, carbonates are known for their therapeutic soaks.
Nicknamed the “beautiful skin hot springs,” carbonated springs feel soft and gentle, which gives a soaker’s skin a smooth feel. Furthermore, these springs remove dirt while improving diseases such as diabetes and liver conditions.
As the name suggests, iron hot springs are renowned for their high iron concentrations. Also known as ferruginous springs, iron springs emerge from their underground source colorless but turn brown upon reacting with the oxygen in the earth’s atmosphere.
Iron hot springs are renowned for retaining heat, improving muscle stiffness, and increasing oxygen levels when consumed. As such, it is a popular therapeutic spring for treating various conditions, including symptoms of anemia and menstrual disorders.
While not all radioactive hot springs are safe for submerging in, those that boast minimal radioactivity are actually known to have positive effects on the human body.
In fact, hot springs featuring small doses of radon are known to boast numerous health benefits, including improvements in gouts, chronic gall bladder diseases, and cholelithiasis disease.
Similarly to radioactive springs, not all acidic springs are safe for swimming. Known for their high acidity, acidic springs are known to peel or melt the skin’s surface. And while springs with exceptionally low pH values are dangerous for the human body, those with a less dangerous acidity are known for healing chronic skin conditions.
Carbon Dioxide Spring
While similar to a carbonated spring, a carbon dioxide spring offers a unique soaking experience thanks to the dissolved CO2 gas. While typically cooler than other hot springs, carbon dioxide springs are known to envelop the body of bathers in bubbles while improving blood circulation by expanding blood vessels and lowering blood pressure.
The Different Types Of Hot Spring – Final Thoughts
While each of the world’s hot springs boasts unique compositions, most of the planet’s thermal pools can typically be classified according to temperature and mineral concentrations.
While there is a level of variability even amongst springs within these categories, understanding the therapeutic properties of a pool’s chemical makeup is a fantastic place to start planning your soaking experience.