With the availability of power on the bike and GPS on the run, the good old heart rate monitor can seem obsolete. And it’s true, the most important pacing tools are (in order):
1. perceived exertion
2. power (bike) and pace (run)
3. heart rate (HR)
But, just because heart rate ranks #3 doesn’t mean it isn’t valuable!
USING HEART RATE DURING A RACE
1. During the race (especially on the bike), a higher than normal / expected heart rate is a warning sign that you might be working too hard.