Imagine experiencing what you haven't experience since in the womb. Floating in an isolation tank has been reported to (lack of better words) shut off your senses and create a feeling of complete full body relaxation. This form of therapy has been known to greatly lower stress levels and help with insomnia. Users have also reported out of body experiences... Well known celebrities that are known to use these tanks are Joe Rogan, Nicolas Cage and the late George Carlin. (to name a few)
In newer tanks, epsom salt is added to the water in the tank to raise the density of the water above the density of the human body, so that the subject floats with his or her face above the water. However, since the ears are submerged when the subject is in a relaxed position, hearing is greatly reduced, particularly when ear-plugs 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. The sense of smell is also greatly reduced, especially if the water has not been treated with chlorine.
A therapeutic session in a flotation tank typically 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 twenty minutes often end with a transition from beta or alpha brainwaves to theta, which typically occurs briefly before sleep and again at waking. In a float tank, the theta state can last for several minutes without the subject losing consciousness. Many use the extended theta state as a tool for enhanced creativity and problem-solving or for superlearning. The more often the tank is used the longer the theta period becomes.