I have a history of a myocardial infarction and afib together with type 2 diabetes. I use one of those finger insert gadgets that gives oxygen together with pulse rate. Im 76 and walk every AM for a mile and I don’t hit 150 until I get to the last minute. My cardiologist knows all of this and is oK with it, but prescribes metoprolol 25mg AM and PM. Does anyone think I am pushing the envelope too hard? Just looking for another opinion.