Quote Originally Posted by emily_in_nc View Post
How old are you? Unless you are > 60, I am not sure you can blame it on age. My DH is 60 and is having the cycling year of his life...he's put in 7200 miles so far this year with multiple centuries (all unorganized, just on his own) and many more 60+ days.

I don't know how he does it either. I've done a few 70+ mile days this year, but most of my rides are in the 40-mile range. And I'm "only" 53. A lot of it is mental.
A lot is just practice. I ride with people in their late 60s and early 70s. Some of them are still very fast. They ride 4 days a week, sometimes more, can ride 60 miles today and 100 tomorrow. They're able to ride a lot because they've worked up to it.