A couple of months ago, my new cardiologist put me on beta blockers. On my first ride of only 10 miles my heart rate was 70 or under. I quit using them and went back to my old meds. Two days ago I saw him and he was angry because I didn't follow his directions. I explained my hobby and what I wanted to do, but it was just blah, blah, blah to him. I told him I would try them again. So today, after being on them for a day, my 33 mile ride was probably my worst ever. Started out OK, felt good, then just lost ALL energy in a headwind on the way home. The internet says I should get used to them somewhat. I'm hoping so.