Re:A HRM is a really REALLY valuable exercise aid. (Score 1)

Absolutely correct! There are several different target heart rate algorithms, all of which are attempts to fit a simple formula to experimental data that has a surprising amount of non-age & sex related variability. fastest-fascist has it right. If you're health, go at what you think is your fastest _sustainable_ pace and back off a bit if you feel nauseous. I regularly exercise at the top end of the target heart rate range for someone 20 years younger.