Why did it feel like I was falling off the roof?

September 30, 2015 2:55 PM

I was on a roof today, getting ready to sweep a chimney. I have been chimney sweeping for over a year and have never felt this sensation until today. I was walking normally up to the chimney and when my left foot came down, I had this feeling like my entire leg got heavy for a split second and then there was a falling sensation and I was definitely alarmed and frightened.

It was a real mindbender. I wasn't even close to the edge of the roof, and it wasn't particularly steep. It shook me up for a few minutes, and I kept thinking, wow, that's never happened to me before. Anyway, I competed the sweep and then I decided to inspect the scene more carefully. I noticed that the spot where I had stepped had a loose shingle that was slightly angled up like a flat arch. I stepped down on it, and it flattened out a bit more. I figured stepping on that and not noticing it gave out must have given me that shocking feeling. Can anyone explain exactly why it felt like that?

posted by jkafka to Science & Nature (6 answers total)

Parts of your brain are on high alert when you're in a dangerous situation (and even if you're relatively used to it, walking on a roof is a dangerous situation to those parts of your brain). They're very attuned to even the slightest difference and will react faster than you consciously process the difference. This was those parts of your brain saying "We put our foot down on something and it moved, so we must be falling."
posted by Etrigan at 2:59 PM on September 30, 2015 [2 favorites]

You thought your foot was down, and assumed that once it touched down it would stop moving downward. When you foot kept moving downward, you were struck by the impression that your foot wasn't *really* down (i.e. that there was nothing under your foot; i.e. that you were falling).
posted by If only I had a penguin... at 3:01 PM on September 30, 2015

Do you wear eyeglasses? I've experienced a missed step/falling sensation when the lower rim of my glasses aligns with the step I'm anticipating in a way that makes me misinterpret where the stair actually is. On the way up, it makes me trip, but on the way down, it makes me think my foot should land before it does.
posted by juliplease at 3:19 PM on September 30, 2015 [4 favorites]

Response by poster: I do wear eyeglasses, and have experienced that as well. This time, however, I wasn't looking at the roof shingles, and the feeling of heaviness in my leg was completely different.
posted by jkafka at 3:34 PM on September 30, 2015

Best answer: I think you experienced a form of vertigo or dysequilibrium. Our sense of equilibrium in three-dimensional space is created by inputs from 1) the vestibular organs of our inner ears; 2) our vision; and 3) proprioception (sense of touch and body orientation; pressure on, and stretch of, muscles). Walking up a roof can be like walking on a moving ship in that perspective is not what you're used to (i.e., your vision is saying: "the roofline is the horizon!") and gravity feels different (i.e., you're walking on a flat surface but being pulled in the "wrong" direction). So your brain has to work a bit harder to maintain your balance and sense of equilibrium. When you stepped on that odd, slightly surprising shingle, your balance system momentarily crashed and you felt as if you were dropping right through the roof/falling.

Similar vertigo sensations happen when you step off a step or curb you didn't see coming. Or sitting in a stopped car and a bus next to you starts moving--you feel like you're moving backwards but you're totally still.
posted by bennett being thrown at 8:33 PM on September 30, 2015 [4 favorites]

Response by poster: Thank you all for the responses!
posted by jkafka at 5:11 PM on October 6, 2015