The key issue is the indication for Propranolol
in the first place. Technically, it does lower your blood pressure and heart rate
and won't let you build your heart rate to the max level corresponding your age and gender. Basically, if taking any medication - especially those prescribed by a cardiologist - you should get a precise advice on what you are and what you are not allowed to do. So, please, check with your doctor the level of exercise you're allowed.