The Underwater Shiver-- What Causes It?

February 5, 2007 8:26 AM

So I'm still trying to pinpoint this one (I keep forgetting to ask it, and Google turns up nothing)-- when one lies down in a bathtub, faceup, and submerges at least their entire ears, they shiver (it's more kind of an uncontrollable, brief spasm of the upper body and doesn't FEEL like shivering, but looks like it). It isn't related to the water temperature, as far as I can tell, and DOESN'T happen when facedown or swimming, etc. Or do other people not have this happen? Do you? I get it every single time, without fail, and have since I can remember. My mom knows exactly what I'm talking about, but my dad insists we're both crazy. Is this just one of those odd reflex reactions like coughing when you have something in your ear or sneezing when you get in the sun? (I also do that one-- always funny to explain to people :) ) Any idea what causes this, though?
posted by dmaterialized to Science & Nature (7 answers total)

Mammalian diving reflex
posted by dmt at 9:04 AM on February 5, 2007

Never heard of it, don't get it, you're crazy.
posted by dobbs at 9:43 AM on February 5, 2007

Response by poster: It sounds like it might be related to Mammalian diving reflex, but it's specifically when I'm faceup-- if I dive into water, or go into a bathtub facedown, it won't happen. It's specifically something to do with water filling my ears at that angle...

dobbs: I AM crazy, but not because of this :)
posted by dmaterialized at 10:32 AM on February 5, 2007

I would guess that it's related to caloric stimulation of your ear canal.
posted by nekton at 12:24 PM on February 5, 2007

This used to happen to me every time I took a bath but now only happens every so often so you and your mom aren't alone in this. I have had it getting into pools and hot tubs so, for me, it's not a bathtub only thing. I wish I had more to contribute but I don't.
posted by LunaticFringe at 12:27 PM on February 5, 2007

Sounds like it's related to Post-Micturation Convulsion Syndrome (aka Piss Shiver). I also experience this when stepping into a warm shower on a cold day. Maybe it has something to do with body temperature or sudden relaxation? It seems to be a different kind of shiver than a cold shiver, to me. More of a shudder. No clue what the evolutionary significance could be.
posted by lostburner at 3:05 PM on February 5, 2007

Best answer: I think nekton is right. Caloric stimulation was addressed a couple of times in one of AskMe's more popular threads (+98). According to one of our most celebrated Answerers:

I don't recommend cold-water calorics for any purpose, by the way. Awake people stimulated with cold-water calorics will vomit reflexively at least 50% of the time. In addition, risks of the procedure include rupture of the ear-drum.
posted by ikkyu2

I'd guess the upper body spasm you describe is an incomplete form of the reflexive vomiting ikkyu2 is talking about.
posted by jamjam at 3:59 PM on February 5, 2007