I've been reading this thread with some interest. I have noticed that I become winded. It is sort of like I'm pedaling at a good rate, maybe 18mph, but when I stop pedaling I am able to catch my breath. When I am pedaling I'm slightly winded, could this be asthma? I was thinking of getting a HRM, thinking I could use it to my advantage. After reading this thread I may just call my doctor.