Survey: Hemoglobin target & EPO

I have been noticing that I am having a very difficult time exercising due to always running out of breath, and I do so faster and easier than other people who don't work out as often or as hard as I do. Is this likely due to my Hemoglobin being at 10.9, or could bradycardia be playing a role as well? My resting heart rate tends to be about 45 due to the beta blockers, but from what I understand it is common for athletes to have a similar resting heart rate, and they don't have problems tiring out while running.

My nephrologist doesn't want to put me on EPO drugs because I have major problems with hypertension, but I really can't stand not being able to run anymore.

If it matters, I'm still pre-dialysis and edema is very mild.