[circlingthesun]

I've never experienced auditory hallucinations before. I did however do a 42 hour self navigated run last year with 0 sleep. After about 30 hours I was visually hallucinating pretty much consistently. Amongst the things I saw was Darth Vader, a giant lego man, our cat sleeping on the trail, spectators that weren't there, a banker sitting at a desk staring at me, a church building that wasn't there, signs that didn't exist, and more.

I think it has to do with the way the human visual system effectively does edge detection and then groups those into objects and attaches meaning. When you are extremely sleep deprived, the edges gets grouped differently and you start seeing things that aren't there.

I could judge what was real or not based on likelihood of me seeing said things in the wilderness, or if I got close enough I would be able to tell what I was really looking at. Another runner later informed me that I had told him he wasn't real when he passed me.

[jmnicolas]

Why would you inflict that on yourself?

I once saw death (exactly as most of us imagine it, dark robes and a scythe) while driving on a highway late at night, I understood the message my brain was sending me: I just took the next exit and slept for an hour (it was too cold to sleep longer, but it made a big difference on my concentration anyway).

[simmonmt]

For the free T-shirt, of course. The finisher's medal, if there is one, is an added bonus. (Not sarcasm)

[circlingthesun]

Ha ha, the t-shirt wasn't even that nice :p

[eMSF]

I can't believe physical exhaustion is not at least as important a part in this. Personally, I skip a night's sleep every now and then to readjust my sleeping patterns, and I've never experienced anything strange after something like 32-36 hours without sleep (but note: no significant physical exertion involved).

It doesn't even feel that bad once you get past the slump in the 20-24 h region.

[circlingthesun]

It might be. I ran 30h race earlier this year and had no hallucinations. I've not done _exhaustive_ research on this, I'm just recalling some undergrad neuropsychology. It could also be the environment. I suspect it's a lot less likely that you'll be seeing stuff that isn't there when you are in a familiar environment as opposed to running alone in the bush.

[moistly]

How do you stay on trail when you’re hallucinating signposts?

[circlingthesun]

GPS watch. Although I did accidentally run back where I came from for a bit O_o

[moistly]

Oof. You ultramarathoners need a watch that signals when you’re going backwards or in circles, like in a car racing game!