So I decided to test it by walking back to work.
Sad... so sad... briskly walking to work certainly counted as exercise for me. The sad part though was according to a heart rate monitor book to get health benifits for your heart you need to exercise for more than 35 minutes at a time.
The walk to work took just under 18 minutes. So to actually help improve my heart I actually need to walk to work and back home again in a single session.
This suggests that the bicycling to work I've been doing doesn't count for trying to get fit, as since I'm probably about 3.5 times faster on the bike than walking, andit's probably only taking me about 5 minutes to get to work, I'm nowhere near that 35 minutes.
So for biking to count I probably need to be biking about 6 miles, instead of the 1 mile I'm doing now. Or I could just walk, maybe if I went around the campus once it would take 15 minutes.
As a bonus though, this means that if I could find a safe street to go 4 or 5 miles on, I could move to a cheaper neighborhood than pasadena.