This sounds familiar. I was an international-level rower for about 8 years when I was younger, and my training regimen was a mix of extremely intense HIIT and l

This sounds familiar. I was an international-level rower for about 8 years when I was younger, and my training regimen was a mix of extremely intense HIIT and long (45min+) steady state workouts. Near the end of my career, I began suffering from very noticeable PVCs (premature ventricular contractions) whenever my heart rate would drop below 45bpm — that is, any time I was at rest, or trying to sleep. My EKG showed mild bundle branch block and echo showed moderate left ventricular hypertrophy. General consensus amongst the cardiologists was that, as long as the remodeling could be explained by exercise, they had no concerns. That was about 10 years ago now. I am far less fit today, and the symptoms described above have largely resolved. My echo shows a mostly-normal LV wall, and I haven’t had a skipped beat in years. That said, this recovery happened during my mid-to-late 20s. Not sure how this would have gone 20 years later.