Heart Rate Does Not Respond To Exercise
I am now 4 months post Biotronic implant, having been diagnosed (I believe) with SSS . Throughout my life I have been very active, including medium distance road-running (several marathons in my 50s and early 60s), cycling, weights, and more recently, recreational rowing (eights). In 2012, at the age of 80 I won the world indoor rowing competition (the "CRASH Bs" held in Boston MA) for my age group.
For most of my life my resting heartbeat has been in the order of 45 bpm; about ten months ago I started experiencing occasional dizziness but was assured by my GP that my heart was fine, so I continued with my regular exercise routine. However, subsequent more intense/frequent bouts of dizziness led to an ECG from which it appeared that I was suffering from some aspect of SSS. Reference to a heart specialist, followed by more tests etc, and I eventually found myself the proud owner of a pacemaker which, I was assured, would make me feel like my old self.
The installed PM is set to maintain a minimum heart rate of 60bpm. The first problem I encountered was that with the PM this setting, I found that I was totally unable to sleep; I enquired if the set rate could be lowered to approximate my long-term resting rate (45bpm) and was told that an overnight rate of 50bpm could be set: this made a marginal difference, but at the time of writing I have to take a sleeping pill to obtain 6 hours of sleep a night at best. I am given to understand that there is some agreement in the medical world that PMs may not to be set below 60bpm. Is this this the case, and if so, why?
From the standpoint of exercise, I have not been informed that my PM is set to any specific upper limit, but in the course of trying to achieve some level of fitness comparable to what it was shortly before my PM was installed, I seem to have lost all semblance of my previous endurance, and find that even short periods of medium intensity leave me panting for breath. My (admittedly somewhat inexpensive) wrist type HR monitor indicates that I can rarely reach a rate much above 80bpm, whereas until 5 months ago I could comfortably reach 130bpm. Or am I just expecting too much too soon?