Im a 'retired' former fanatical cyclist, could ride an average of 18+ mph lone riding 50 mile circuits, (which isnt THAT great but not shabby either) commuting, leisure, fitness, 6000 miles pa.
Tuberculosis, pneumonia and complications took me off the bike for two years, tried to get back to fitness in 2015 but then osteoarthritis took hold..im a mere pleasure rider now, dont do many miles anymore.
Long since accepted that was then, this is now..doesn't bother me.