Thermal Springs

THERMAE (from the Greek thermos - hot), natural healing self-flowing sources of warm and hot water, regardless of the degree of their mineralization and gas content. In geology, thermae are called sources whose temperature exceeds the maximum average annual temperature observed anywhere on the globe, i.e., 34°. In balneology, it is currently accepted to consider thermal sources those with a temperature not lower than 20°. As a criterion for evaluating the thermal properties of a source in balneology, the physiological principle is adopted. The measure for such an evaluation is the average temperature of the human body. Thermae, according to the temperature attribute, are divided into: a) hypothermal, or body temperature-lowering (from 20° to 34°), b) indifferent (from 34° to 37°), and c) hyperthermal, or body temperature-raising (from 37° and above). A characteristic feature of thermal sources is the constancy of their temperature, which does not change throughout the year. The high temperature of the source is caused by the great depth of the soil layers from which the water emerges. In soil layers, heat progressively increases towards the depth and, starting from the so-called belt of constant temperature, rises by 1° every 33 m, reaching, depending on the depth of the water emergence, very high temperatures (e.g., Icelandic geysers - 100°, Dumna in the Himalayan mountains - 100°, Aguas de Campanilhas in Mexico - 96°). Most hot sources contain a greater or lesser amount of dissolved gases and solid constituents originating from the natural rocks of the earth's crust. Thermae with a content in 1 l of at least 1 g of dissolved solid constituents and gases, primarily CO₂ not less than 0.25 g and H₂S not less than 1 mg per 1 l, as well as rare elements, belong to the group of mineral waters in the narrow sense of the word. Thermal sources with a dissolved solid residue content of less than 1 g per 1 l with the absence or content of CO₂ and H₂S below the specified norms, as well as devoid of rare elements, belong to the so-called chemically indifferent thermae, akratotherms (see). All this division into indifferent and non-indifferent thermae is largely conventional and is subject to fair criticism, since the activity and balneodynamic effect of water often do not correspond to the degree of its mineralization. The use of thermae is predominantly external—in the form of a bath, and depending on the temperature of the source, the water for baths is heated or cooled. To maintain the constancy of the water temperature during bathing, it is recommended to perform bathing in baths or pools (piscines) with running water (practiced, e.g., in Abastumani and Tskaltubo). Internal use depends on the nature and chemical composition of the water. Also for enemas, douches, and inhalation. Indications for the use of thermae vary depending on the temperature of the source and its chemical composition, mainly: chronic articular rheumatism, chronic and subchronic injuries of the locomotor and supporting apparatus, chronic inflammatory infiltrates (in the small pelvis, etc.), syphilis in late stages, etc. Contraindications are general for thermotherapy and resort therapy (see Balneotherapy), and in addition, depending on the chemical composition of the water of a given source and the gases released during bathing.