In my case, I experience hypersensitivity. Noises are LOUD and tactile feelings are BIG. When one's physical body is receiving input constantly and at such a strong level, it can quickly become uncomfortable and then overwhelming. The body may go into a state of warning. Sensory information has exceeded perceived safe levels. The body thinks it's in danger and decides to either escape the threat or overcome it.
The tricky thing is, while I may be experiencing this, others may be talking, interacting, and working as normal. Their bodies may think that things are comfortable and safe, while mine is entering a panic-state. I want to behave like a responsible adult, and I know there isn't really any danger, so I try to deny my body's input. I push down its feelings and warnings. But this usually doesn't last long. My body *knows* its in danger and if I won't run or fight, it will do that for me to help me. It short-circuits my attempts to maintain balance and pulls me into overwhelm, where basically my system says - YOU ARE OVERWHELMED! DISENGAGE! At this point, my emotions get pulled in and I feel INTENSE anger and fear. I feel like I'm being buried alive in my own body. And it feels so miserable that I have to stop talking, stop making eye contact, and leave the situation (or disengage if I feel like I can't physically leave). It may take hours of quiet time and space for my body to recover from its panic, cool its intensity, and feel safe and content again.
This experience is emotionally difficult and sometimes is actually physically painful. For example, if I'm in a warm, loud room long enough, my ear feels like someone is stabbing it. My skin also reacts at times, breaking out in rash, itching, or some other uncomfortable sensation. Usually, though, the feelings are low-level and more like an undercurrent. That can make it hard to recognize them until they reach an intense level, especially because I spend so much unconscious time pushing the feelings down, out of the way. It's as if I'm telling my body, "Hey, you're distracting me. I'm fine. Leave me alone." But my body is only trying to warn me :( When I ignore its warnings, I usually regret it.
Over the past few years, I've been trying to better recognize my body's sensations and reactions. If I can pay attention to how I feel in a situation, I can better predict how it's going to react and better adjust to it. I don't want to be a slave of my body, but I do want to treat it with respect. I can do that by paying attention to how it feels, acknowledging those signals, and then deciding how to respond. I'm still learning, but the awareness has been an important step in the journey.