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What Happens to Your Brain in a Sensory Deprivation Tank

Sensory deprivation has a reputation for bringing subjects to a state of peace and calm, and its supporters say it eases many physical ailments. Let’s walk through what it is and how to make the most of a facility near you.

What is a Sensory Deprivation Tank?

Sensory Deprivation tanks, or just “float tanks”—the practice is just called “floating” by practitioners— are temperature-regulated, epsom salt-filled, sound and light-proof tanks that isolate occupants from sensory input. The salt allows people to remain afloat without effort. The temperature of the water and air are skin temperature, so the subjects cannot sense where their body ends and the air or water begins.

The tanks are completely soundproof, and a button allows floaters to turn the lights off when they are ready to begin the experience. An intercom system is available at all times should a floater need assistance. Most floats last around one hour, but floaters are free to leave at any time.

John C. Lilly, who was known for his strange and innovative scientific and medical research, developed the first sensory deprivation tank in 1954. He called it Restricted Environmental Stimulation Therapy, or REST. Lilly researched paranormal activity, interspecies communication and LSD through personal use. Unfortunately, his eccentric tastes made his research fall flat in the scientific community. However, the recent resurgence of flotation therapy has increased research on its effects and benefits.

Travel to the Upside Down?

The show “Stranger Things” used sensory deprivation to allow its character Eleven to mentally travel to the Upside Down, but will that happen in your local float tank? Probably not. However, a study conducted in 2009 showed that just 15 minutes of near-total sensory deprivation was enough to trigger vivid hallucinations in many test subjects.

This study, published in the “Journal of Nervous and Mental Diseases,” indicates that the hallucinations experienced during sensory deprivation are caused by faulty source monitoring. Source monitoring errors are memory errors that occur when a person attributes an experience to a fictitious source. For example, a person may say that they saw a flying squirrel when they were children, when in reality they just saw one in a film.

The Many Benefits of Floating

Depriving the brain of sensory input can engender a state of calm, but that doesn’t mean brain activity is lower. In fact, brain activity increases greatly because the brain is not busy translating incoming information. Similarly, this break in stimuli allows the brain to build memory and sort information. Research done in this area shows an increase in creativity after a float session.

When flotation tanks were first conceived, researchers and neuroscientists used them to test the effect of sensory deprivation on non-physical aspects like creativity, human connection and concentration. More recent research suggests that sensory deprivation may actually be effective in reducing the body’s stress response, inducing deep relaxation and quieting mental chatter. Floaters experience many additional benefits, including treatment of insomnia, chronic pain, anxiety, depression and addiction. A study from the '90s exploring sensory deprivation as a treatment for addiction was effective in changing some addictive behaviors and was promising for others.

The stance of the National Institute of Health is that meditation has proven effective in lowering blood pressure and easing symptoms of anxiety and depression, among other things. Research is ongoing, but scientists are finding that floating reduces anxiety in a way that rivals pharmaceutical medications.

Big Reward, Light Risk

Float tanks can reduce your stress response, increase memory and reduce anxiety. They are promising in treating chronic pain and lowering blood pressure, all without the need for insurance or a co-pay. But what are the risks?

Fortunately, float tanks have very few risks. The water is shallow and turning over in the tank takes quite a bit of effort, so falling asleep and thus inhaling water is very unlikely. Most people who understand what to expect in a sensory deprivation tank are able to enter a state of relaxation and finish the duration of the float without incident. Some people may experience claustrophobia and need to end the float early.

Be sure to check reviews for your local float facility to ensure there are no glaring sanitation issues. Ask about the facility’s sanitation procedures if you have specific questions.

Find a Float Near You

Self-care is en vogue these days, and it seems floating is one of the best ways to treat yourself, brownie sundae not included. Early research in this therapy is ongoing, but if you want to experience the many benefits for yourself, you can search for a location by ZIP code using Flotation Locations listings.


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