Dr. John Lilly, a medical practitioner and neuro-psychiatrist, developed the floatation tank in the 1950s. During his training in psychoanalysis, at the National Institute of Mental Health, Dr. Lilly commenced experiments with physical isolation. It was argued that if all stimuli were cut off to the brain then the brain would go to sleep. Lilly decided to test this hypothesis and, with this in mind, created an environment, which totally isolated an individual from external stimulation. From here, he studied the origin of consciousness and its relation to the brain.
In the original tanks, people were required to wear complicated head-masks in order to breathe underwater. In our float rooms, Epsom salt is added to the water to raise the density above the density of the human body, so that you float with your face above the water. However, since the ears are submerged hearing is greatly reduced, particularly when earplugs are also used. When the arms float to the side, skin sensation is greatly reduced because the air and water are the same temperature as the skin, and the feeling of a body boundary fades.
A therapeutic session in a flotation room lasts an hour. For the first forty minutes, it is reportedly possible to experience itching in various parts of the body (a phenomenon also reported to be common during the early stages of meditation). The last 20 minutes often end with a transition from beta or alpha brainwaves to theta, which typically occur briefly before sleep and again at waking. In a float tank the theta state can last for several minutes, many use the extended theta state as a tool for enhanced creativity and problem solving or for super learning. Floatation therapy has been academically studied in the USA and in Sweden with published results showing reduction of both pain and stress. The relaxed state also involves lowered blood pressure and maximizing blood flow.
Floating can be passive or active, depending on the purpose. For relaxation, one simply floats and becomes the observer of the body/mind system. Active floating has many different techniques. One may perform meditation, mantras, and self-hypnosis, utilize educational programs, etc. The idea of active floating is that, when the body is relaxed, the mind becomes highly suggestible and any action taken during these states will enter the information into the sub-conscious. Floatation therapy may be used complimentary with other bodywork and healing methods.