At 63 yrs old i started riding last october and 'got into it' dec or jan of this yr. There are many measurable benefits as other poster have described but it's the mental benefits i enjoy most. I have more energy, can move faster, think quicker, sleep better and wake up refreshed, over all feel a whole lot better. I am a business owner and riding my bike is the only time i don't think about work, business and money ... i enjoy listenin to the bike, the breeze in my face and thinkin about the N+1 of course.
My wife rides with me half the time and it's one of our favorite times to talk !!!