I have had test after test but so far my doctor says everything looks normal. I am 21, Ive been having heart palpitations for over a year that mainly occur if Im in heat/humidity or doing work that makes my body temp rise. Also, I occassionally have a hard time breathing. It feels like Im holding my breath though Im not. For some reason it happens more when Im standing with good posture than when Im sitting or slouched over. I am an active woman and love being out and doing things but this heart issue is really getting to me. It feels like mu heart skips a few beats, struggles to get back on track, and then I get a hot flash and feel exhausted. Like I said though, my doctor ran whole bunch of tests and they were all clear. Anybody have anything similar?