Adrenaline caused heart racing

I have seen a cardiologist for my arrithymias which are not life threatening, however, he feels I'm very sensitive to adrenaline.  When I exercise my heart rate goes up to 150/160 quickly.   Could this be a function of my being out of shape?  Also, he has put me on a low dose beta blocker (Pindolol) to block the effects of adrenaline, but I'm afraid to take it because I typically have low blood pressure.. sometimes 90/60.   Should I try the Pindolol and see what happens?  Is there any way my body can become less sensitive to adrenaline?

[Jerry_NJ]

Yes and yes, and maybe... you present a number of possibilities and I think most are part of the answer.  If you are not in a physical condition to handle the exercise level you undertake, then the HR and adrenaline would go up faster than if you were exercising below you conditioning - and the beta block in a low dose you doctor prescribed is worth a try.  Was the advice to use just before exercising or to use it on a regular/daily basis?  

A beta blocker may push you BP down a bit, but I think you will adjust to that.  I assume you low BP doesn't currently give you problems like dizziness.  It may be part of the reason your HR jumps when you start to exercise.  Don't know but that too could be relate to adrenaline sensitivity.  If you have problems with the BP, that is something you may want to address on its own merits.  Too much salt can cause high BP in some people, I wonder (and do not know) if more salt in one's diet would tend to raise BP.