Isolation tank

An isolation tank, originally called a sensory deprivation tank (a.k.a. float tank, flotation tank or sensory attenuation tank) is a lightless, soundproof tank with high epsom salt (magnesium sulphate) content filled with salt water at skin temperature, in which individuals float. They were first used in 1954 to test the effects of sensory deprivation.

Flotation is widely advertised on the internet as a form of alternative medicine with claims that it has beneficial health effects.

The isolation tank was developed in 1954 by John C. Lilly, a medical practitioner and neuropsychiatrist. During his training in psychoanalysis at the US National Institute of Mental Health (NIMH), Lilly experimented with sensory deprivation. After 10 years of experimentation without taking any psychoactive substances, he tried floating in combination with a psychedelic agent, mostly LSD (at that time he was a researcher at NIMH, and LSD was legal in the US).

In 1981 there were about $4 million in sales and rentals in the industry, and expectations were that the market would grow, spurred by the movie Altered States which came out in 1980. According to one person in the industry, in the 1980s the rise of AIDS and the fear of shared water reduced demand for flotation centers. By 2013 flotation was more popular in Europe than the US but had undergone some growth in the area around San Francisco; at that time a low-end tank cost about $10,000 and an hour flotation session cost about $70.

Flotation has been widely advertised on the internet as a form of alternative medicine that has a number of health benefits, but the claims are often exaggerated and poorly-evidenced. Despite the lack of scientific support, people have sought treatment from flotation for many conditions including muscle tension, chronic pain, hypertension, and rheumatoid arthritis to PMS.

A 2005 meta-analysis of clinical trials that had been conducted at that time, found that the trials were generally small and highly prone to error, but given that limitation, use of isolation tanks, (called "flotation REST" or "restricted environmental stimulation therapy" in the literature) appeared to be useful for stress management.

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Wikipedia