Nearer to sixty than 50, still running close on 2000 miles a year, done 9 off road half marathons this year.
The difference is in my twenties, I ran a lot faster and could sustain the pace, now I just plod along and it takes me a full week to recover from a race, rather than a couple of days like it used to.
Also my tolerance to ale has massively reduced with age and the hangovers seems to last for days, as a result if there`s nothing in pub I want to drink ( no real ale ), I`ll happily drink soft drinks.