Water has been used medicinally for thousands of years, with traditions rooted in ancient China, Japan, India, Rome, Greece, the Americas, and the Middle East. There are references to the therapeutic use of mineral water in the Old Testament. During the Middle Ages, bathing fell out of favor due to health concerns, but by the 17th century, “taking the waters” at hot springs and spas became popular across Europe (and later in the United States).
Hydrotherapy is broadly defined as the external application of water in any form or temperature (hot, cold, steam, liquid, ice) for healing purposes. It may include immersion in a bath or body of water (such as the ocean or a pool), use of water jets, douches, application of wet towels to the skin, or water birth. These approaches have been used for the relief of various diseases and injuries, or for general well being. There are other therapies that may include the use of water as a part of a technique, but are not included in this review, such as colonic irrigation/enemas, nasal irrigation, physical therapy in pools, steam inhalation/humidifiers, drinking of mineral water/”enriched” water, coffee infusions, aquatic yoga, aquatic massage (including Watsu®), or aromatherapy/baths with added essential oils.
Modern hydrotherapy originated in 19th century Europe with the development of spas for “water cure” ailments, ranging from anxiety to pneumonia to back pain. Father Sebastian Kneipp, a 19th century Bavarian monk, spurred a movement to recognize the benefits of hydrotherapy. His methods were later adopted by Benedict Lust who immigrated to the United States from Germany in 1896, and founded an American school of naturopathic medicine. Lust claimed to have cured himself of tuberculosis with Kneipp’s methods, and hydrotherapy was included as a component of naturopathic medicine. In modern times, a wide variety of water-related therapies are used, some of which are described below.
Sitz bath: A Sitz bath is administered in a tub that allows the hips to be immersed in water. Sitz baths have been used in the management of back pain, sore muscles/muscle spasm, body aches, sprains, hemorrhoids, pruritis (itching), inflammation, rashes, anxiety, for wound care/hygiene, and to promote relaxation. For various ailments, different temperatures may be used, and minerals or medications may be added to the water.
Arm bath: For a cold arm bath, the arm is placed in a basin of cold water with the water level reaching just above the elbow. A rising temperature arm bath uses the same principle as a rising temperature footbath.
Foot bath: Cold foot baths involve placing the feet in a bath filled calf-deep with cold water. “Walking in water” involves stepping on a non-slip mat placed under water. For warm/rising temperature foot baths, the feet are immersed in water at body temperature. Hot water is gradually added until the temperature reaches approximately 103-104 degrees Fahrenheit. Therapy may last for 10-15 minutes. Caution is warranted not to cause burns.
Rising temperature hip bath: These baths are administered in tubs initially filled with shallow tepid water. Hot water is gradually added until levels reach the navel. A common temperature is 103-104 degrees Fahrenheit. The bather may then be wrapped in warm dressings.
Cold rubbings: This technique may use linens or towels soaked in cold water then wrung out and vigorously rubbed on the upper and lower trunk or the entire body.
Douches: “Douches” may be carried out with a watering can or hose. Treatments can be applied to any area of the body, with the intention to relieve tension or pain, or to affect blood flow.
Steam bath/sauna: Heat may be used to cause sweating, and these techniques are variably included in the definition of hydrotherapy. People should not spend more than 15-20 minutes in a steam bath or sauna, and individuals with medical conditions such as heart or lung disease should avoid prolonged heat exposure (as directed by a qualified healthcare provider).
Wraps: Hot or cold wet wraps may be used around various parts of the body. This technique is sometimes used with the intention to reduce fever or foster relaxation. Hot fomentation involves the application of warm liquid or moist heat with towels to the surface of the body.
Spa/hot tub/whirlpool/motion-based hydrotherapy: These therapies are sometimes used in people with wounds, chronic musculoskeletal pain, or inflammation. People should be aware of the risk of introducing infections into wounds, and the importance of keeping wounds clean.
Purifying/mineral bath: Prior to immersion, solutes or other components may be added to water, such as sea salt, lemon juice, turmeric, Epsom salts, baking soda, chlorine bleach, or essential oils.
Dead Sea balneotherapy: There are numerous published articles regarding the use of therapeutic uses of water immersion in the Dead Sea (and other salt water bodies), particularly for chronic skin conditions. Because this therapy also involves prolonged exposure to sunlight, it is not clear to what extent possible benefits are due to the water, to minerals/high salt content in the water, to sun exposure, or to a combination of factors
Water birth: Potential benefits of giving birth in water have been explored. Research is not definitive in this area.
Aquatic physical therapy/Watsu®: Physical therapy in pools is a well-established technique that takes advantage of buoyancy and resistance to movement in water. Watsu® is a form of bodywork conducted in pools.