ric,
What do you think of Sally Edwards reasearch on HR? I have had good luck with her info in the books in the past. Sally's site Basically her formula which I have seen before, just not sure where, is 210 - age/2 - 5%weight + 4 (male). This yeidls me a max of 180, which is close to what I saw in 01/02 when I did some hard riding. I had a max of 182 recorded numerious times on my HRM when I d/l that data. (Hard climbs) I was 47 then.

Right now I am using her Zone 3 and riding to lose weight, 126-144 range.