I'm an athlete who runs in extreme fitness events. My last event was a 63 mile run and I plan to run 100 miles in less than 30 hours next year. So why am I taking Beta Blockers? I had a heart attack 30 days ago. My EF is 70 and the attack was caused by a blockage in the artery. I was also diagnosed with reactive airways a couple of years ago and haven't had much problems with them until now. The Beta Blockers seem to really make me short of breath and makes me feel bad in general.