ric, thanks for the info an the link. Right now that formula is about right as I go anarobic in the mid 140's.

nutbag, 126 = 70% and 144 = 80% for me I do hard rides at the top to 155, which my doctor told me not to go above yet (high BP) and moderate ride 125 - 135. Today is easy/recovery ride and I will hold 125 - 130 for 25 miles.