Humankind has been using bodies of water for a variety of activities for a very long time—for transportation and the extraction of resources, but also for recreational, therapeutic, and wellness purposes. One of the more recent applications is flotation, which was developed in the 1950s by US neurophysiologist John C. Lilly at the National Institute of Mental Health. The body floats in warm, saline water, shielded from outside stimuli, in a special isolation tank. A state of deep relaxation is said to occur. Commercial providers advertise their services with promises ranging from changes of physiological markers, bodily self-healing, and restoration, to changes in brain function, cardiovascular and respiratory changes, an enhancement of the immune system, and skin revitalization.
Stories like that of John Lennon, who is said to have overcome his heroin addiction with the aid of floatation tanks, add to the reputation of the method as a silver bullet. Although some claims made by commercial providers are probably exaggerated and lack supporting evidence, many studies do confirm that floating in warm salt water has positive effects, especially for stress management.
Sources: Goldman, Albert, “The Lives of John Lennon”, Chicago, (2001).
Jonsson, Kristoffer and Anette Kjellgren, “Curing the sick and creating supermen – How relaxation in flotation tanks is advertised on the Internet”, European Journal of Integrative Medicine, vol. 6, issue. 5, (2014): 601-609.
van Dierendonck, Dirk and Jan Te Nijenhuis, “Flotation restricted environmental stimulation therapy (REST) as a stress-management tool: A meta-analysis”, Psychology & Health, vol. 20, issue. 3, (2005): 405-412.