Is HR or power the best way to improve bike performance?

Those of us who have been endurance junkies long enough can remember the first clunky heart rate monitors–big strap on devices that you could set ranges for to monitor your training. Around that same time (late-’80s), SRM was launching the first power meter, but that technology remained cost-prohibitive for most.

Heart rate monitors quickly became both easier to use and considerably less expensive–by the ’90s most cyclists were gauging their training efforts by measuring their heart rate. As power meters became a more accessible piece of equipment, many cyclists started to use power as their primary means of measuring their effort during workouts and races. Now it’s not unusual to find athletes who don’t pay any attention to their HR data on the bike, electing to focus purely on their power output. Do those athletes have things right? Or is there still value to be had in training based on heart rate?

Heart rate vs power

At its simplest, your power meter is measuring how hard you are working on your bike (your power output) – how many watts you are putting into pushing the pedals. Your heart rate is a measurement of how your body is reacting to that effort.

Heart Rate

Easy of use: Pretty much every training watch incorporates wrist-based heart rate monitoring these days. For most people, the data provided from the wrist-based monitors work pretty well, but for more accuracy (and for those who just can’t seem to get decent numbers from their wrist), adding a chest strap is an easy fix.

+ Expense: You likely already have one.
+ Set up and testing: A simple ramp test will provide you with some decent numbers to work with for your training zones, and many sport watches will also provide easy testing and monitoring to help you develop appropriate training levels.
+/ – Steady: Heart rate training works really well in steady state or easy training scenarios. There’s a lag between an effort ramping up and you seeing any changes in your heart rate (a positive component of training with a power meter – we’ll get to that momentarily), so you’ll get the most out of using your heart rate monitor when you’re setting it to maintain either an easy or steady-state effort for a longer period of time.
+ Overtraining warning: One sign of extending yourself too much in your training can be an elevated heart rate, both resting and during activity.
– Fluctuation based on conditions: Altitude, hydration levels, fatigue, temperature and how recently…