Besides, variations in your resting HR from day to day mean you'd have to recalibrate your 65% WHR (for example) each day.
wHR uses your resting HR as calculated "every once in a while", not each day. The idea is that two runners both with a max of, say, 180 bpm, but one with rHR of 45 bmp and the other 60 bpm, will be in different "aerobic places" at 75% maxHR (135 bpm). wHR tries to take account of this. So runner 1 would use 139.5 for 70% wHR where as runner 2 would use 144 bpm. I started with Paker's book, so I use wHR ... and also Fetch site, where I log my training, use wHR.
