I don't know the answer to your question, but I'm sort of in a similiar situation. Instead of Atenolol, I'm taking Inderal for palpitations and rapid heart beat. It works great keeping my heart rate down and it works ok at fighting the palpitations, but I can't get my heart rate up either. If I walk briskly, a good pace for 20 or 30 minutes or so, I'm still not going over 105 bpm! The doctor says this is ok, and that I could take a smaller dose, 10mg instead of 20mg if I want my heart to beat faster. For obvious reasons I'm reluctant to do that because normally, when I'm not excercising I want my heart rate lower - 72bpm which it is with the 20mg of Inderal 3x per day. The other thing about taking Inderal I don't like is it makes me so tired. I don't even feel like excercising at all! I'm so lethargic on 20 mg 3x. If I take it 2x per day my heart speeds up too much even at rest. Anyway, I don't know if there's an answer to how high should you push it. It might not just go up that high anyway. Good luck let us know what the doctor says.
Forget the count mine is over 90 even if i'm sitting. No I am not over weigh I weigh about 128 and am 5"3'. I take 200mg. atenolol and 20mg benazapril .I was recently put on felodipine but had a bad reaction to it. My legs and feet swelled up so bad I could barely walk. WHEN I REALLY GET GOING WATCH OUT IM A FLASH. I'V TRIED ALL THE MEDS. EVENTUALLY MY BODY GETS USED TO THEM AND I HAVE TO SWITCH. just do what you can. When you can. GOOD LUCK.
I'm a runner and was recently on the beta blocker Metoprolol for PAT's. I exercised as much as I was able to and didn't worry about over-taxing my heart. In fact, my doctor gave me the go ahead to do whatever I wanted. The point is, the beta blockers would only allow me to reach a certain point in intensity, no matter how hard I tried. This has been very difficult to deal with - I kept running but had to stop several times on a 10k run.
My doctor switched me to Cardizem (calcium channel blocker) to see if that would make a difference. Since I've only just started it and it will take time for the beta blocker to leave my system, it's still too early to tell. However, the pharmacist told me I should notice a big difference.
Once on beta blockers (or similar meds), there is no simple formula (like 220-age) for figuring maximum heart rate. It varies from person to person and med dosage etc. You need to determine your maximum heart rate by trial and error. Ideally, you would have a treadmill stress test under a cardiologist's supervision and based on that, he would tell you your target range. That not being available, the next best thing is to exercise moderately (12-14 on a scale of 6, at rest, to 20, maximum effort possible) and see what your rate is. Then afterwards, whenever you exercise try not to exceed that rate. In my case, I take a variety of meds for afib and high BP that keep my at rest heart rate in the 50's. However, when I slow jog (say 5 mph), after 10 minutes it reaches 120-130 BPM. I try not to exceed 130 when doing exercise of any type.