I have just recently started using a HR monitor, and have found some interesting results.
I have chosen 142 as a good aerobic hr to train at. When I ride at 140 bpm for 40 minutes (on trainer) I feel that I get a fairly good workout right now. If I were to run at 140 bpm for 30 minutes, I feel like I am barely moving.
I have felt, in the past, I have trained more anerobically than not, without having a good foundation. I have since committed to training more aerobically, both running and biking. I have read Moffetones book, and have ordered a Sally Edwards book, but it has not arrived. My main goal is to do some harder rides (Mnt Mitchell) next spring ('06), but will run twice a week, riding the other 3 as training for the ride.
What do you make of the difference in perceived exertion and heart rate of biking vs. running?