Sensory deprivation is achieved through floating in a type of isolation tank that cuts off all sources of sensory experience: sound, sight, smell and touch. Another way floating is referred to in research studies is “Restricted Environmental Stimulation Technique,” or floating-REST.
Float tanks that are used for inducing sensory deprivation are filled with water that is almost the exact same temperature as the floater’s body, along with high amounts of Epsom salt (made from magnesium sulphate). The salts allow you to remain restfully floating at the water’s surface in complete silence and stillness.
During the entire session, floaters generally feel light and peaceful, without needing to exert any effort to stay afloat.
As you’ll learn below, flotation-REST’s positive effects impact physiology, including lowering levels of cortisol, lowering blood pressure and promoting positive feelings of well-being. Studies show that increased mindfulness and decreased stress during a sensory deprivation tank float session reduce markers of bodily distress syndrome (BDS).
Researchers often use the term ‘BDS’ to describe negative physiological changes that take place when someone is under a lot of stress. These BDS signs are now tied to things like fibromyalgia symptoms, chronic fatigue syndrome and somatization disorder.