What do you think it is?
50 is not really abnormal heartrate for a 15 yearl old. Aww, I wish I was that young again, but I digress. 60-100 is textbook normal range.
THe better shape he is in hte lower it will be. A famous marathon runner named Alberto Salzar had a heartrate of around 30. So low because of how efficient it was, he was in a junctional rhythm, meaning his secondary pacemaker took over.
The things I would worry about if I had a son of 15, someday I hope. Would not be heart disease. So I will be out of my league in giving you advice. But probably I guess hypothyroidism. Other metabolic disturbances, depression and yes stress.
I mean given the very broad and limited information you provided.
It literally could be anything.
I would ask the doctor to tick off a list of the most life-threatening worrisome stuff. I meah is he in shape or fat? Does he have diabetes or too skinny? Is he using drugs or a straight A student, break up with a girlfriend. Who knows?
My ultimate recommendation would be to communicate tremendously with your son. Teen anst is nothing new and he is not unless a very rare case having heart disease. Hope that eases the mind a bit and helps. Sorry I do not have better advice
I'd go with panic attacks, too.
Is he involved in any activities that he'd prefer to not be involved in? Gym class, maybe?
The mind is a terrible thing to lose.
It's true that being a teen is stressful. I remember those days. But that's a pretty low heart rate (is he an athlete?). And fainting, vomiting, being cold and visual disturbances are not normal. Is he eating and drinking OK? Some of it sounds like dehydration and/or low blood sugar. It might be good to get a second opinion. Hope he gets to feeling better soon.