Beta blockers don't do well for me. Years ago Doc put me on atenolol. While it did take my heart rate down aprox 20 bpm it was like hitting a brick wall when I was working out. I'd get my heart up to 130 bpm and the fatigue and shortness of breath would kick in. I'd have to slow down to cool down speed, took a long time to recover my energy level. I convinced my doctor to take me off of the atenolol, within six months I had a silent heart attack and ended up with triple bypass surgery. After the surgery my cardiologist put me on metoprolol which has the same effect as the atenolol. I'm also on Norvasc and Lisinapril.
When that happened your doc should have done an EKG on the treadmill to see if you had blockages to your heart muscle blood supply. Classic case of Angina, you start to exercise, but your heart can't supply enough oxygen rich blood to your body because it isn't receiving sufficient oxygen itself. You run out of energy quickly and eventually if you push it too hard you damage your heart muscle and have a heart attack. I got to the point I couldn't go around the yard a single time with my lawnmower without stopping to catch my breath. Went to see my doctor, he had me in my cardiologist the next day- 4 stents placed 2 days later. I feel fine now, but I'm on Metropolol for reduced heart rate and lower my blood pressure and Statins to keep my stents from getting blocked again... felt great ever since... and that was 12 years ago...
Younger brother had the same thing happen to him, but he ended up with a five way bypass and same meds... no problems for him either...
Bob
