Came across a rider last year on the stiffest part of a long hill. I was surprised I actually overtook someone- it is not a hill for the weak. As I passed him- I looked and he was struggling a bit but he was older than me and riding a bike 20lbs heavier and with knobbly tyres.

Waited at the top to make certain he was OK and on chatting- He was getting his last ride in before having the right knee replaced. His left knee replacement was about 18months old and worked well so he was getting the right one done. And he was the same age as me- It's just that the hill made him look old. Now I know why I get pitifull looks from the 20year olds that pass me while they are in the big ring.