I am 60 been riding on and off my entire life, but very steady the last 10 years.
I ride sometime mountian bike, sometime single speed cruiser, sometime 5 speed cruiser, very seldom a road bike. Usually ride 5 times a week 15 to 30 miles at a time. It is a good workout on those single speed cruisers.
I have always been facinated by fixed gear, but was always told it would ruin an old mans knees.
But last fall I bought a cheap one rode it a few times and loved it. So far this spring I dont ride anything else, I cant believe how much fun it is. I am looking for another one, I like to have several bikes so if one gets a flat or fails, I can hop on another one till i get around to fix the first one.
anyway any of you old guys that have been thinking fixed, give it a try most likely you will be hooked very fast.