I'm 76 and counting. I try to get three or more rides each week.
At least one of 60 km on our RailTrail. That usually makes for a speedy ride. Today I took my old Bianchi Nyala (3x7 gearing nd no suspension) on a much hillier 60 km route. Total climb 746 metres but that was on pavement, max grade 11%. Yeah the downhills were also great.