Hey everyone, this is something that has been happening occasionally for a few years now. I'm a 19 year old male, frequently weight train and do cardio as well. I've had this thing where if I bend over too abruptly (I've noticed it's made worse when my stomach is full or I breathe in) my heartbeat will go from normal to probably 100-120 bpm and palpitating, can last anywhere from 30 sec to upwards of 10 minutes. It's happened bending over to pick something up too fast, jumping up to grab a pullup bar, or even initiating a deadlift; seems anything that compresses the vagus nerve has a chance to trigger this.
I've gotten regular checkups with a cardiologist and they didn't find anything out of the ordinary (no arrhythmias etc, no diagnosed AFib or anything of the sort), so my heart is very healthy overall but I'm still not sure if these episodes are something I should worry about. They disappear as fast as they come, like I can actually feel my heartbeat come back to normal and it's a scary feeling, it almost feels painful when it returns to normal. I'm afraid one day it'll try to reset and just go into cardiac arrest or something. I've tried to research this online but can't seem to find anything that fits. Closest thing I've found is maybe the vagus nerve gets compressed somehow in spinal flexion, or that bending over creates increased intra-abdominal pressure (but that topic doesn't say anything about it causing prolonged palpitations).