I am a 57 year old guy. In the past 5 years of bike riding, I have really benefited. I have lost 40 lbs (now 128 lbs) and can can now negociate some pretty steep hills found around here. I started out purchasing a 70's era Univega 12 speed from my neighbor for $75.00. Riding with my co-workers around Griffith Park challenged me to compete and stay with the younger riders in the group. I started longer rides, then bought a good Tandem frame from ebay and built it up with parts equal or better than on the KHS Alite tandem. My wife was now able to join me on my rides- we started training by riding to Seal Beach on the San Gabriel river bike path (about 42 miles round trip). We took a vacation on the tandem, boxing up the bike and taking the train to Oakland, then reassembled the bike, loaded the panniers on, and took the ferry to San Francisco. We rode the bike down the pacific coast 575 miles back home, it was a real adventure! I had reserved lodging about every 50 miles, as my wife didn't like the idea of camping. There were desolate areas and steep hills south of Big Sur to San Simeon, but we made it. You could look down the coast and make it as far as the eye could see in only one day by bike.
Anyway, I have started to commute to work (in Los Angeles) about 40 miles round trip.