> there is precedent for this, you don't really feel your heart beating or hear your blood rushing most of the time. the brain learns which signals aren't important to you

At the risk of a kind of odd tangent, I had a very weird experience a couple years ago where I woke up one morning and my entire body felt like it was "external" to my feeling, for lack of a better description. Getting up and walking around made me feel queasy because I could feel everything in my abdomen sloshing around, and lying sideways made me feel what I assume is how claustrophobic people feel in tight spaces because it felt like there were multiple surfaces around me instead of just the one I was lying on. I had severe brain fog to go along with it; the words coming out of my mouth felt like what I wanted to say, but it didn't feel like I was choosing them; normally my speech feels almost like a distillation of my thought process, but this felt like they were just spontaneously coming out without any thought process to generate them. My wife (still my fiancee at the time, but we had been together for several years) apparently couldn't tell anything different about me outwardly and said she wouldn't have been able to tell anything was wrong other than what I was telling her. The sensation didn't last all day, but after it left I had an odd numbness everywhere. The numbness was gone by the next morning too, but a couple weeks later the brain fog and numbness came back (albeit not quite as strong as it had been originally), and it's only been gradually fading away since then.

The experience (and the later experience that's still going on for a while now) has made me realize just how much my perception previously had been, let's say, "curated" by mind. One thing I've noticed is that even when the physical sensation isn't present, the "reaction" to the sensation will still occur. For example, I remember a time when I was shoveling large amounts of snow, and I suddenly noticed that I was taking large amounts of time between each shovelful, which had been happening instinctively due to how much I needed to catch my breath, but even then I still didn't physically feel tired or winded. Plenty of times I've woken up somewhat earlier than usual and tried to get back to sleep but not been able to, and eventually I realized there must be reason, so I'd have to actively think about whether I was thirsty or hungry or needed to use the bathroom, and then suddenly realized that one of them was actually the case. Pain is one of the weirdest cases, even with my numbness being a lot more mild than it was for the first year or so, because I still have the reflex that I'd expect from a sudden severe pain even if I don't feel it nearly as strongly.

I don't know for sure how much of this generalizes to everyone else, but the experience has definitely made me reconsider some cognitive theories that didn't seem plausible to me before. The idea that our brain basically tricks us into "remembering" feeling something as the reason for us taking a certain action seems pretty consistent with how I was would act the same way in circumstances where I normally would expect to have sensations causing me to act that way without being able to actually feel the sensation. In some ways the philosophical idea of consciousness being an illusion don't seem as crazy to me as before either, because it's clear that the reality I experience is only perceived through the lens of my biology, and I can't come up with a strong argument against the idea that my sense of "self" is just an evolutionary hack for handling some parts of my body (with the parts not benefiting from conscious management being actively hidden from whatever part of me feels like "me").