Brief History
Salt caves have been used going back to hundreds of years ago to the Grecian age. It is said that Hippocrates considered salt inhalation beneficial to treat respiratory issues. This ancient healing treatment was rediscovered during Eastern Europe. Whether discovered to take shelter, by accident, or as salt miners, those who have spent time in the salt cave have noticed positive effects on their respiratory conditions and their overall health. In the 1950s physicians developed methods to simulate conditions of salt caves, and in the 1980s, Russians began integrating salt rooms as part of their clinical treatments. Since then, salt rooms have been opening across Europe, Scandinavia, and North America.
Benefits
Salt is super absorbent, ant-bacterial, and anti-inflammatory. The presence of magnesium and calcium and other trace minerals in the salt dust floating in the air contribute to the therapeutic benefits the salt caves provide such as relief from asthma, allergies, colds, ear infections, smokers cough, cystic fibrosis, COPD, sinusitis, skin conditions, like acne and psoriasis, rosacea, skin aging, eczema, swelling and inflammation according to the Salt Therapy Association.
According to Dor. R. Richard Leinhardt, he says "Saline in the lungs is key to eliminating toxins that we either inhale or otherwise come into contact with, and salt allows the body to excrete impurities through ion exchange."(1) Also, according to Dr. Joseph Marino, it "decreases the thickness of the mucous, thereby allowing the body's innate clearing mechanisms to sweep away the secretions, improving drainage and diminishing bronchial sensitivity."
How it works
Active Halotherapy is a therapy that involves a room or chamber (which varies in size depending on where you go) and a halogenerator that grinds pharmaceutical-grade sodium chloride into dust and emits the dust into the room. The micro-sized particles are dispersed into the air in a room or chamber. The microscopic particles of dry scodium chloride are inhaled into the respiratory system.
Passive Halotherapy imitate natural salt caves, and it is not truly a halotherapy but a salt room for relaxation and well-being, due to the lack of halotherapy equipment. The rooms contain large amounts of different types of salt, from Dead Sea, Mediterranean, Caribbean, Rock Salt, and the popular Himalayan. This method does not use a halogenerator. Instead, the airflow, humidity and temperature is regulated, therefore creating an environment free of allergens and pollutants. 
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