What Is A Sensory Deprivation Tank And Is It Safe To Use?

Imagine spending about 60 minutes in a shallow (a foot or less) pool of water filled with about 2,000 lbs of salt. You float, because you're in no danger of drowning. You're in a pod, cut off from anything that might stimulate your senses — no lights, no sounds, and you're in complete darkness. After a while, you could feel like you've become one with the water — not sure of where your arms and legs end and where the water begins. That thought might freak some of us out completely, but for others, that could be just what the doctor ordered.

Sensory deprivation or floatation tanks have been around since 1954, when a neuroscientist named John C. Lilly invented the tank to study consciousness by cutting off most senses (except hearing and smell). The tanks themselves were not commercially accessible until the 1970s, when commercial centers were set up and marketed for their health benefits (via Healthline).

Floatation tanks fell out of fashion towards the 1980s, but they're making a 21st-century comeback under a new name. Now called "Restricted Environmental Stimulation Therapy" (REST), the tanks are viewed as a way of treating conditions including post-traumatic stress disorder (PTSD), panic disorder, agoraphobia, or social anxiety disorder. One 2018 study even found that a single session could bring about "a strong reduction in [the] state [of] anxiety and a substantial improvement in mood in a group of 50 anxious and depressed participants" (via Very Well Health).

While REST therapy is safe for many people, it isn't for everyone, particularly those who don't like the idea of enclosed spaces or who might be afraid of drowning. New York Psychiatrist Phillip Muskin tells CBS, "Some people might find that very restful. Some people might find that it freaks them out." But, he stresses that these breaks are beneficial because they empty a person's mind. "Attention is a biological phenomenon. When you empty your mind, be that by breath, floatation, meditation, exercise... it works by allowing our brains to do some discharge of the junk and let us go back to work," Muskin says.