I have been riding my bike around town for years, but never had a long commute until last spring (7 miles each way). I have never been much into exercising but riding the same route every day provided a kind of benchmark. Every hill was a daily challenge. Every stale green light was a sprint. It definitely helped having a bicycle computer to monitor my progress. I wore a jersey and mountain bike shorts with a chamois so I could change into fresh clothes for work. It helped that the majority of my route was long uninterrupted stretches on a popular bicycle artery/scenic drive.

As far as fitness goes, I definitely lost about 10 pounds and gained a more defined abdomen.