I'm 71. Yes, but not directly due to age and I intend to return to my previous levels. I've alluded to this in the 50km/50m challenge thread. In June '24 I was hit by a tractor at +/-32/33 mph. This resulted in six months effectively off the bike. Last autumn my wife was diagnosed with stage 4 cancer and while she is perfectly "well" (not as daft as it sounds) this has resulted in understandable changes in our lives.
My riding has reduced from 2/3 times a week, 120/150 miles in total, often more in summer, to one ride of 50/60. Only 3100 miles in 2025, my target would be 5000+. I can still sit with youngsters, in their 50s, in a group and happily knock out 120 mile days. What has gone is my ability to climb, I can still ride all the local climbs but far slower than 18 months ago.
What I need is to return to my previous weekly rides and I am finding ways to reorganise life accordingly. I work with a PT, stretch out 4/5 times weekly and follow gym routines 3/4 times a week. I'm riding a very local loop, 16 miles and 1400 feet, to build the climbing when I'm short of time. I've shifted 3kgs and have another 4kg to go.
My two regular buddies, 65 and 69 have made huge improvements in the past 8/9 months. It's a question of what one wants, not age.