I'm 36, and the wheels have fallen off running wise. I was never one of those guys that never got injured, then after 30, the body starting revolting against hard training, or even large amounts of training. I retained some fitness for a couple of years, but I'm a slug now compared to my better days. I ran a 5k in 19:30 recently, and it was a little too hard to be proud of, but I did get under 20 minutes. Baby steps.
But, that being aside, the rest of my life I feel very young. I have MUCH more energy to do stuff than when I was training hard. Sex drive is greater. I have more energy to put into hobbies like learning the guitar. I love vacations now as I don't have to worry about getting a run in all the time. I put on 25 pounds, still look athletic, but am no longer accused of being "too" skinny and I can tell it helps in many areas.
I loved my running life, but I consider it over now, at least to do it as a daily experience. There is a lot to do in life besides running, and not running really helps finding those other things.