Let’s start with the basics: a float tank is essentially the perfect bath tub. They vary in size, but the typical tank is 8′ long and 4′ wide. Air is allowed to freely flow in and out, and the door never locks or latches.

It holds about 10″ of water, which is saturated with 850 pounds of Epsom salt. This creates a solution more buoyant than the Dead Sea, and you float on your back about half in and half out of the water.

The water itself is kept at the average skin temperature (93.5° F), which allows you to lose track of your body. The tank is sound-insulated and, when you turn off the light, completely dark.

No gravity, no touch, no sound, and no sight.

The buoyancy puts your body into what is essentially a zero-gravity environment: your muscles and bones get to relax, your joints and spine decompress, and the strain on your circulatory system is greatly reduced. It’s basically like your entire body breathing a sigh of relief.

With no external stimuli coming in, your system stops worrying about all the background tasks that usually keep it occupied—mostly related to not dying. Your fight-or-flight response gets a chance to kick back and stop bossing your brain around, lowering your production of adrenaline and cortisol. Instead, studies show signs that your dopamine and endorphin levels rise, giving you a natural mood high which often lasts for days.

Sensory deprivation effects us in another notable way; as our brains become stimuli starved, their reaction is to start creating their own stimuli. Swirling nebulas, gorillas on surfboards, and frolicking Labradors are only a sampling of the visualizations that people have reported from their time in the tank.