Posted 7/2/2013 8:27 PM (GMT 0)
I am pretty sure that you are having associative anxiety regarding your heart rate and cardiophobia.
Your biggest fear is rooted in the health of your heart/cardiovascular system...therefore it makes sense that when you try to increase your heart rate...you have feelings of panic
Many people with panic disorder have trouble with exercise because of the feelings associated with it. The physical sensations of working out can be quite similar to panic symptoms. Increased heart rate and body temperature, shortness of breath, sweating, ect.
Remember that you have had all of the tests come back as healthy indicators that you are fine...as well as the fact that you are young and have no big risk factors. Add to the fact that you do have an anxiety issue, and it all points to the fact that this is stress related.
Make your attempts at exercise slow and steady. Even if you are feeling symptomatic, try to continue and I bet you will find that they soon fade out.
Best wishes!
S.C.