I am currently on Inderol (beta blocker) for migraine management. As a result my heart rate is super low (38bpm - active) and I am unable to run more than 600m without needing to rest. I am an extremely fit and active person so this is really difficult for me. Does this normalise? I have only been on it for 40 days. I am also losing feeling in my hands and feet (circulatory).