Sensory Deprivation - relaxing or crapola?

I hold ‘alternative medicene’ in the same regard as dirt. However, sensory deprivation tanks seem like they could be relaxing, if nothing else. Is there any evidence that these tanks are harmful in any way? Perhaps shutting down the senses for so long is harmful…

Don’t know using a tank is harmful, but watching Altered States (1980) sure is.

Does this mean you think it’s a good thing or a bad thing?

Back in the mid-'80s we had a place here in Houston where you could rent some time in a Lilly tank. And one night I did; climbed in for a couple of hours. The bath was heavily laden with epsom salts (to make me a little more bouyant than I’d be in just water) and the air and water temperature were maintained (I don’t remember the exact details) such that you would be unlikely to be aware of the waterline. Absolutely pitch black once the door was closed.

The fellow who operated the place interviewed me before I went in; he told me some people have a bad reaction to weighing anchor with the outside world.

Once in and away it was only a short time before I became acutely aware of the sounds of my own body (ever hear your eyelids ratchet open?). But those soon faded and I don’t know where I went, until I became vaguely aware of the piped in jazz that was started to tell me my two hours were up.

The proprietor told me he’d spent five hours in that day and, if I hadn’t been a Cub Scout, he would have failed to charge me for the time. One of the mellower folk I’ve dealt with.

When I left, I was like heated butter. I think I was as relaxed as I’ve ever been. I don’t know what New Age verbiage might be keeping company with sensory deprivation tanks these days, and I’m generally allergic to New Age thought, but that’s my experience with the tanks.

Richard Feynman, the Nobel-laureate physicist (among a bunch of other cool stuff) tried sensory deprivation a few times, and wrote about it (among a bunch of other cool stuff) in great detail in his memoirs, Surely you’re joking, Mr. Feynman!. It’s a very good read (don’t worry, there’s almost no actual physics in it), and I highly recommend it.


When in the tank, did you have any orientation, such as knowing which way was up?

Why I ask is that one of the more interesting positions I have occasionally found myself in involves not sensory deprevation, but sensory overload. A few times I’ve been caught in large holes (violently recirculating water at the base of drops and waterfalls) and not had any idea which way was up. Obviously these experiences were of short duration, or I would not be here, but each time the feeling of total disorientation has stuck with me as being very interesting.

I tried a sensory deprivation tank back in the late 70’s, but for me the experience was anything but sensory depriving. The high saline content of the water burned my skin, and after a short time I got this tremendous ache in my neck from the lack of anything to hold my head up.

I went to a flotation spa once; at first they assumed I would float in the uncovered tank. But I asked for the covered tank. I think if I go again I’ll try the uncovered version.

The only problem I had was the hallucination of suffocating. Objectively I know I had plenty of air to breathe because they kept the lid open a crack. But I kept feeling I wasn’t drawing in enough oxygen, so a couple times I sat up (not easy to do in that water) and put my face by the opening to breathe. Well, that spoiled the experience. Apart from that, it was a very calm experience. It seemed that for a person who didn’t know how to meditate, it would induce a meditative state willy-nilly. Since I was already experienced at meditating and yogic relaxation, it didn’t add much.

My yoga training in fact may have gotten in the way, since I associate yoga with deep, full breathing. Whereas in the tank shallower breathing would have sufficed. In yoga I use the breath to relax body and mind. But the tank does that for you without your doing anything, so deep breathing just doesn’t fit in there.

According to this site,, in a tank there is no pull of gravity. That is an incredible achievement.

In “Eye of the Cyclone” John Lilly actually talks about reaching a point where he was dissatisfied with the experience he was getting in the tank, so he started dropping acid before he got in.

That book convinced me that Lilly was far nuttier than Leary. Entertaining, though.

[QUITE]According to this site,, in a tank there is no pull of gravity. That is an incredible achievement.

Har. They could have said “There’s no subjective sensation of gravity”, but in the context of that essay, I can’t fault them too much. Lighten up, so to speak.

Well, I didn’t get that [QUITE] right, and didn’t preview - sorry.

(but it demonstrates that vBulletin doesn’t actually pair up their open / close syntax, but simply treats the closing “tag” as a separate substitution and produces a dangling “closure”. They should be smarter than that.)