You're lucky. I've clocked in almost 3000km and over 20'000m of elevation gain cycling last year. I also swim and hike. My resting heart rate dropped by about 1BPM and it's nowhere near as low as yours.
I think resting heart rate is mostly genetic, from what I read it tells very little about fitness - if you're already fit you may already be at your "optimal" heart rate. If you stopped exercising it may go up.
EZ-E|1 year ago
Refusing23|1 year ago