Floating Away: The Science of Sensory Deprivation Therapy

By Shelly Fan | April 4, 2014 8:30 am

float tank

I tried not to panic. I was floating effortlessly in a pitch-black tank filled with salty, skin-temperature water, wearing earplugs and nothing else. Within minutes I could no longer feel the sponge in my ears or smell the musty scent of water. There was no light, no smell, no touch and – save for the gasping of my breath and drumming of my heart – no sound.

I was trying out North America’s avant garde drug: sensory deprivation. Across the continent “float houses” are increasing in popularity, offering eager psychonauts a chance to explore this unique state of mind. Those running the business are quick to list the health benefits of frequent “floats”, which range from the believable – relaxation, heightened senses, pain management – to the seemingly nonsensical (“deautomatization”, whatever that means). Are these proclaimed benefits backed up by science or are they simply new-age hogwash?

A Sordid (and Sensationalized) History

Why would anyone willingly subject him or herself to sensory deprivation? You’ve probably heard the horror stories: the Chinese using restricted stimulation to “brainwash” prisoners of war during the Korean War; prisons employing solitary confinement as psychological torture. Initial research studies into the psychophysical effects of sensory deprivation, carried out in the 1950s at McGill University, further damaged its reputation, reporting slower cognitive processing, hallucinations, mood swings and anxiety attacks among the participants. Some researchers even considered sensory deprivation an experimental model of psychosis.

However, despite popular belief, sensory deprivation is not inherently unpleasant. According to Dr. Peter Suedfeld, a pioneering psychologist in the field, these stories are rubbish. “(The prisoners) were bombarded with overstimulation – loud group harangues, beatings and other physical tortures,” he explained. Similarly, the original studies at McGill University used constant noise and white light – that is, sensory overload ­ – rather than deprivation.

In fact, an analysis in 1997 of well over 1,000 descriptions of sensory deprivation indicated that more than 90% of subjects found it deeply relaxing. To escape the provocative name of “sensory deprivation” and its negative connotations, in the late 1970s Suedfeld’s protégé, Dr. Roderick Borrie, redubbed the experience with a friendlier name: REST, or Restricted Environmental Stimulation Therapy.

Today, the two most frequently used REST methods are chamber REST, which involves the participant lying on a bed in a dark, soundproof room, and flotation REST, which involves floating in buoyant liquid in a light- and sound-proof tank. The latter, first developed by John Lilly in the 1970s and now widely commercialized, is what I decided to experience myself.

The Brain Without Input

Floathouse, a newly opened sensory deprivation tank centre in Gastown, Friday May 10, 2013. THE CANADIAN PRESS/Eric Dreger

A flotation tank at Vancouver’s Float House.

The Oasis flotation tank was much chunkier than I expected. Designed to fit the average man with arms outstretched, the 90’’ by 48’’ industrial-looking behemoth nonetheless operated with only a slight hum.

Mike Zaremba, the co-founder of Vancouver’s Float House, explained that the tank was filled with Epsom salt-saturated water heated to skin temperature. Try to steady yourself in the water until it settles, Mike told me, then you won’t be able to feel the water. There was little pre-float briefing save for a reassuring remark that I could terminate the experience at any time – a disclaimer that Suedfeld encouraged based on experimental data showing it decreased anxiety.

I climbed in, closed the heavy door and was engulfed by total darkness. Almost immediately after settling in the warm, womb-like tank one of my senses disintegrated: my body orientation. The vestibular system in the inner ear contributes to the sense of spatial orientation, and together with proprioception – that is, the sense of the relative positions of neighboring body parts – it allows an overall perception of the body’s position, acceleration and movement in space. Without external cues, I felt like my body was spinning like arms on a clock face; the illusion was so strong it brought about a few waves of nausea.

Deprived of external stimuli, the brain generates its own. Parts of the visual field light up in unrecognizable shapes, which eventually morph into more complex manifestations such as dots, lines and grated patterns. With the advent of brain imagining techniques, scientists have been able to capture the brain basis of such finicky visual hallucinations during sensory deprivation. In 2000, one such study found that volunteers’ visual cortexes became more active after less than an hour of visual deprivation.

Hallucinations may also occur in other sensory domains. For me, it was auditory: initially, I heard a beautiful aria drifting in and out, like music from a faraway phonograph; soon it morphed into a full symphony before settling into a simple, tribal beat. Incredibly, I did not recognize any of these tunes; my brain was spontaneously generating them.

Creative Juices

Some of Suedfeld’s work suggests that flotation facilitates creativity. A small study of five university professors found that six 90-minute float sessions allowed them to generate more “creative” ideas, which coincided with a self-reported increase in free imagery and remote associations. Similarly, in a study with 40 university students, a single hour of flotation increased their scores on a standardized test used to measure creativity.

Although boosts to creativity are a prime selling point for float houses, evidence supporting them is sparse. A far better researched effect of flotation is that it enhances performance in a variety of athletic and musical tasks that require high levels of concentration and visual-motor coordination, including basketball, tennis, archery and jazz improvisation. In a sample of 13 jazz students, four sessions enhanced their technical performance one week after the last flotation experience, suggesting the possibility of lasting benefits.

Suedfeld speculates that flotation may enhance creativity and performance in a manner similar to that of sleep or meditation. Research has shown that during resting states the brain repeatedly rehearses newly learned skills and consolidates recently acquired knowledge for long-term storage. Some studies have also shown that the resting brain is particularly adept at synthesizing information from a wide range of brain areas to solve tough problems – something you may have experienced daydreaming in the shower.

However, Suedfeld says, compared to sleep or meditation, such “twilight” states are more easily achievable without prior training or conscious effort via flotation. Advancements in brain imaging techniques may someday help us understand how these twilight states compare at a neurological level.

Experiencing Weightlessness

Cognitive perturbations only make up half of the flotation experience; far more noticeable are the physical effects. Within minutes of entering the tank, I coaxed my muscles to relax and allowed myself to sink into the warm cocoon of water that supported every inch of my body. Moving around required a surprising amount of effort; submerging my head under water was plainly impossible. I was content to lay still.

In the early 1980s, a group of psychologists at the Medical College of Ohio initiated a series of experiments that looked at the physiological responses to REST. Both within and across flotation sessions, blood pressure and levels of stress-related hormones dropped – effects that persisted long after the cessation of the last flotation experience. In 2005, a meta-analysis further confirmed that flotation was more effective at reducing stress than other popular methods such as relaxation exercises, biofeedback or relaxing on the couch.

These results prompted researchers to investigate whether flotation could help patients with stress-related disorders. The treatment was used as a primary intervention for disorders as diverse as hypertension, headaches, insomnia and rheumatoid arthritis; all of these studies showed positive effects in small sample sizes. Those suffering from intractable chronic pain particularly benefited from weekly REST sessions: their level of perceived pain dropped, their sleep improved and they reported feeling happier and less anxious. An ongoing project is investigating the use of flotation for fibromyalgia pain management with positive preliminary results.

A Flotation Resurgence

There’s no doubt that scientific research backs some benefits of flotation. Still, the research has been imperfect. For one, studies are generally small. For another, it’s not obvious what counts as an adequate experimental control for flotation: Relaxing in a dark room? Going about daily activities? The mysticism and recreational drug use that surround flotation have also slowed research on the technique by the broader scientific community.

Nonetheless, Suedfeld is hopeful for the future of his life’s work. “There is a resurgence of the research since the 2000s,” he told me, “(mostly) replications and extensions of work done in the 1980s-90s.”

Float houses will continue to advertise their outsize lists of the treatment’s benefits. But the key to wider scientific acceptance might be for scientists to rein in theirs, Suedfeld says. “’Be courageous in what we try, cautious in what we claim,’” he said, borrowing an aphorism from psychologist Neal Miller. “I’ve always liked that one, and I think we should adopt that.”

As for me, when I left the float house reflecting on my session, I was suddenly painfully aware of the incessant car honks and busy footsteps from the bustling streets – noises I had almost forgotten about in my hour of disconnection. Was the experience transformative? No. But I felt calm and relaxed for the first time in weeks. To me, that’s good enough therapy.

 

Images courtesy floathouse.ca

CATEGORIZED UNDER: Health & Medicine, Top Posts
  • http://www.mazepath.com/uncleal/qz4.htm Uncle Al

    Magnesium sulfate (Epsom salt) is typically added to the water to increase its density. Mg(2+) is psychoactive, and it diffuses through hydrated skin. People do not like being alone when they are in poor company.

    The brain demands input. Go deaf in a frequency band and your ear (that part of your brain) whistles at that frequency. Amputate a limp and the phantom limb in its place screams at you, Hire a brilliant high autist only allocate four days of work/week, and he must create (hence Google’s eldritch conquests).

    Enjoy being yourself as you will. Self-awareness is overall better than a gram chasing a damn – but text benefits from punctuation.

    • http://jayarava.blogspot.com Jayarava

      I can find no evidence that Mg++ is psycho-active. Not all amputees experience phantom limb pain. Not all deaf people have tinnitus.

      • wendyo123

        my uncle recently got a nearly new
        black Volkswagen Touareg SUV by working off of a pc… blog link B­i­g­4­1­.­ℂ­o­m

      • http://www.mazepath.com/uncleal/qz4.htm Uncle Al

        doi: 10.1016/j.neuropharm.2011.12.029 Circulatory magnesium potentiates analgesia through N-methyl-D-aspartate receptor antagonism. Don’t claim climate when weather is blowing the shingles off your roof.

        • http://jayarava.blogspot.com Jayarava

          “The action of NMDA receptor channel antagonists was studied in native NMDA receptors of hippocampus CA1 pyramidal neurons isolated from rat brain slices.”

          I think your conclusion is beyond an extrapolation too far.

    • Gary Deezy

      What were you smoking when you typed this?

      • http://www.mazepath.com/uncleal/qz4.htm Uncle Al

        Reality wrapped in peer-reviewed technical literature, ignited by disgust at faith versus reproducible observation.

        • Emkay

          the faithless go to hell…

    • Emkay

      ” People do not like being alone when they are in poor company”, if you are the ‘company I can see why… Sober up and post something that makes sense…
      “Self-awareness is overall better than a gram chasing a damn” WTF does that mean?… Do not reply, what a waste of time and space…

      • Aviyl

        Does it hurt to think? If you don’t understand, that’s your problem. You say all this, then command this person to not reply to your wanderings. “Do not reply, what a waste of time and space…”. This shows gross disrespect for others but mainly yourself.

        • Emkay

          sswwooosshh…right over your head!

  • Mea

    Did this in the 80s when Altered States was big. It was awesome. It takes 30 minutes for your nerves to stop seeking stimulus then all goes quiet. I didn’t hallucinate but the relaxation was unmatched. Everything turns back on when you come out and you’re super alive..you tingle for a long while. Lights are brighter, sound louder. I would do it again in a heartbeat.

  • Cali Bound

    How do you not get puckered night after night?

    • Garrett K

      “The reason for the inclusion of the Epsom Salt is partially cosmetic: the increase in ionic strength prevents some of the temporary skin wrinkling (partial maceration) which is caused by prolonged immersion of extremities in pure water. However, magnesium sulfate (Epsom Salt) can also be absorbed into the skin, reducing inflammation.”

      As per Wikipedia :)

  • Nikhil

    meditate instead!! This experience will be like a snapshot then.

    • Garrett K

      Do both! Both are very beneficial, and have a very synergistic relationship with each other. I’ve found that my mind quiets very quickly when spending time in a float tank, and this transfers to my sitting meditation practice.. allowing me to get to a deeper state more rapidly :)

      Less head noise through floating = a variety of benefits during sitting meditation.

      • Nikhil

        With your access to the float gone,your peace will also go away..But with meditation whatever is the state of your surroundings you will remain immersed in the centre of silence. I have experienced it ..it would be much better if you experience it WITHOUT the float.. I am not against this practice but just being dependent on this is not the way. As a beginning you can use it but later you have to be on your own..

        • Garrett K

          Out of curiosity, how much time have you spent in the float tank? I, and many others, would disagree that the peace disappears without access to the float tank. Numerous people have found that it lasts for a significant amount of time. With meditation – I’ve found that the meditative peace lasts for maybe a day. So I have to do it again the next day.

          How many years worth of prior meditation did it take you, until you became immersed in the centre of silence? Also, why would it be better to experience it WITHOUT the float? And do you have any ways to guide a mother of 4, who is very stressed out, to that point? Also, why do you feel that you can only use it at the beginning, and that you ‘have’ to later be on your own?

          • Nikhil

            First i want to make it clear that I am not against anyone using it. But just stopping with the float >?!
            1. Peace disappears? It never disappears ,it is just that you lose access to it.
            2. Meditation is not just sitting in a particular place closing your eyes and observing your thoughts, meditation is being being mindful in each every action you do, observing every action you do..no matter what you DO. Eating food? eat with awareness ,getting your children ready ? do it with awareness no matter what you do,who you are, it does not matter.
            3. Experiencing it with the float “only” you will fool yourself into thinking that this is it, this the ultimate I can experience. Be mindful in every act you do .. And by your own you will experience something much more substantial than what you experience with the float.
            4. At times you may find yourself losing your awareness , don’t make that an issue. Making it an issue will not help. Sooner than later you will find yourself being in a state of awareness more and more…

            Did you read this with awareness ? ;)

          • http://blogs.discovermagazine.com Paula Carnes

            Anyone up for trying this water experience should first read “Testing the Spirits” by Hillstrom pages 60-63. No matter what your religious persuasion you may want to think twice about sensory deprivation. Hillstrom mentioned John Lilly, MD who used sensory deprivation himself. After years of this experience he was not so excited about it. (I have to add that he also used LSD.) But read the book for information on how this might affect you. I think I will stick to mindful swimming myself.

          • Nikhil

            Mindful swimming ! Yeah sounds like a better and natural option!

          • Emkay

            5. damn, I have to go to work all day!

          • Nikhil

            haha…you can be mindful in your workplace too!

  • Mabel

    I’d like to try it at least once. It sounds cool.

  • Gunasekhar Tirupati

    I went for a sensory deprivation using floatation tank in San Diego area in 2011 as I had read much about it earlier through various sources. After that 1 hour session I felt relaxed and one stunning difference is that the senses had become very sharp. Colors became vibrant, hearing became acute and presence of mind improved for few days. For those who already practice some kind of meditation or relaxation the changes will be subtle, but for others it will be really dramatic. If we had cheaper ways of inducing similar sensory deprivation at homes, it would be very very beneficial.

  • Dimitri Ledkovsky

    Definitely on my bucket list.

    • http://blogs.discovermagazine.com Andrea Mckeeby

      Agreed !

  • Vanessa Hooper

    DO NOT discourage people from mediating whatever form they choose! I have a hard time sitting for meditation practice anymore since I broke my back in a car accident. This tank sounds like heaven to me. If the mother of 4 thinks getting away from stimulus would help her, (& I don’t see how it couldn’t) then let her find peace. We’re not all on the path to enlightenment in this life, so DON’T discourage people from taking steps in the right direction!

  • george

    hkkkj

  • 18235

    1960s hippies did this—-and they wound up being down on their luck 1970s me generation types.

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A collection of bright and big ideas about timely and important science from a community of experts.

About Shelly Fan

Shelly Xuelai Fan is a PhD Candidate in Neuroscience at the University of British Columbia, where she studies protein degradation in neurodegenerative diseases. She is a science writer with an insatiable obsession with the brain. She mulls over neuroscience, microbiomes and nutrition at her personal blog Neurorexia.

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