A few weeks ago I noticed my Garmin was reading a heart rate a bit lower than normal but what was puzzling was the fact that I was not wearing a heart rate strap. It was picking up a signal from one of my buddies-- a guy with a killer sprint. I filed that bit of info away and took note of when he would fade on a climb and the corresponding heart rate. It's a rare day when I can take him in a sprint so about a mile out I ramped it up to where he was right at his limit and at 200 meters he was cooked and had nothing left for the city limit sign.
Go ahead, ask how badly I feel about that tactic