why can't i breathe and run normal like others?

Question

I cant seem to breathe normal when i run alot,
i would like start breathing soo hard and then i get dizzy.
my heart would beat fast too when i get tired. i do a lot of physical stuff, but i would get soo scared when i start to do the mile run and etc, whats wrong with me? i went to the doctors and stuff but they said that my blood pressure and stuff is normal. its just that my heart beats fast unlike others...?
sometimes i would pass out too. its crazy... whats' wrong with me && what do i do?

i'm 15 btw.

Answer 1

if you are new to exercise, then it could be that you just need to start off slow and work your way up to it.

you could also have asthma, which if you are active, an inhaler will help open your lungs back up so you can breath.

Answer 2

How old are you? How often do you work out? Maybe you just have poor physical endurance, which you could build up over time by working out on a consistent basis.

This is assuming that what you say the doctors have told you is true, that your blood pressure and stuff (assuming you don't have asthma) is normal.