Beatles icon John Lennon did it to kick his heroin habit. Quarterback Tom Brady does it to stay on top of his game. Actor Russell Brand has compared it to “being in the belly of a whale.” And comedian Joe Rogan, whose hugely popular podcast draws tens of millions of listeners, is almost single-handedly credited for its renaissance. He describes sensory-deprivation float tanks, where you drift like a gently bouncing fetus in an amniotic pool of salt water, as one of “the most incredible pieces of equipment for self-help and introspective thought that you could ever find.”

Invented in 1954 by the quirky neuroscientist John Lilly (he was also a proponent of telepathic communication with dolphins), the water-filled pods offered a trippy experience for early enthusiasts who believed they could expand their consciousness and creativity. The tanks fell out of favour during the AIDS crisis in the 1980s because of public health fears, but improved technology, the mindfulness trend and celebrity endorsements such as Rogan’s have them making a splash once again.

There are dozens of float centres in cities across Canada, from Drift Float in Sherwood Park, Alta., to Rest Nest Float Club in Toronto and the Floatation Centre in Halifax. You can even buy your own personal tank (prices range from $2,000 to more than $30,000). The Bright Float Pod, for example, boasts “a sleek, modern sanctuary” with a cavernous interior and piped-in sound. There’s also an annual Float Conference, “the world’s largest float tank event,” held in Oregon every year. In Sweden, where there are more float tanks per capita than anywhere else in the world, physicians will write prescriptions for their patients to bob around.

“There are a lot of stories about how floating has changed people’s lives — a guy came in the other day for back pain, and when he came out he said it was the most transcendent experience of his life,” says Jay Ziebarth, owner of Zee Float in Hamilton. “Some people see visions, and others go back to their early childhood memories.” Users float naked in water that’s been heated to body temperature and saturated with about 400 kilograms of Epsom salts (making it twice as buoyant as the Dead Sea). The closed container blocks out all light and sound, offering cocoonlike comfort, meditative bliss and sometimes a spiritual awakening. It’s thought that time in the tank allows brain waves to transition from the logical beta state to the dreamlike theta state, thus paving the way for visualizations, inspiration and insight.

Some people may take years to achieve a deep theta state in meditation, says Ziebarth. “With floating, you can get there in 45 minutes.” One convert describes the tanks as “portals into the swirling depths of the psyche” or “spacecrafts to take you face-to-face with the void.”

The research is thin, but a meta-analysis of 27 small studies shows that float therapy has a positive impact on mood, blood pressure and stress levels. It’s currently being studied for its therapeutic potential to relieve chronic pain, and some suggest it could also help with symptoms of PTSD and ADHD.

In a float tank, you are truly disconnected. That can be challenging for people who find it difficult to be alone with their thoughts for more than an hour. Ziebarth says some of his millennial clients who are glued to their smartphones can’t always make it through 90 minutes. But for a host of others, it’s a release from the constant swirl of thoughts that threaten to drain them. They’re able to just go with the float.

This story first appeared in The Observer’s April 2018 edition with the title “Escape Hatch.”