Aging and fitness - mostly by bicycle?
My opinion is that if one has decent daily health, a relatively stable life situation, riding routes and fair weather - then getting old doesn't suck. Best to throw in some weight training, flexibility exercise and brisk walking.
The weather here in Seattle was nearly perfect (for outdoor activities) from early June thru September. I had more days of cycling & hiking than I can remember (maybe ever),
. It wasn't the highest mileage in either activity, but most consistent. Any 3-4 day breaks may have been spent babysitting grandkids, which is a lot more exercise than 25 miles on the bike. Zero kayak days tho'.
When does OLD start? Surely a 65+ discussion, unless one beat themselves up physically, or got 'crop dusted' with some chemical agent, or drank Flint MI water, or lived downwind/downstream from nuclear weapons sites, chemical or industrial sites, mines, etc.