The Data Addiction

We are all guilty of it. You upload a ride, APIs work overtime, and within minutes you are staring at the charts. One line that constantly catches my eye is “the blue line.” In Intervals.icu, it is called Chronic Training Load (CTL). In cycling jargon: your ‘Fitness’. Strava also displays this information (only in the paid version), as does TrainingPeaks.

If that line goes up, you feel like a champion. If it drops after a recovery week, panic strikes as if all your hard-earned gains vanished in one fell swoop.

Zone 2… It’s that easy, steady training ride you must do to build your aerobic engine, usually completed while whistling a tune. Your heart rate stays perfectly low, and after three hours, you step off the bike feeling fresh as a daisy. Granted, it can be frustrating: you were probably overtaken by almost every other cyclist out on the road. Did I actually even train? You feel like you could almost put your cycling kit back in the closet without washing it.

Many amateur cyclists train blindly based on standard formulas or use the well-known “220 minus your age” heart rate rule. You cruise along nicely, sweat pours from your forehead, and afterward, you feel like you had a ‘good workout.’ But does your fitness plateau after a few months anyway? If so, there is a high probability that you are unconsciously riding in a physiological no-man’s-land: the notorious Gray Zone.

To ride faster, you need to know what is really happening under the hood of your muscles. And you don’t need to be a bio-scientist to understand it. It all revolves around understanding two (magical?) thresholds: LT1 and LT2. What are these thresholds, why do we use a specific zone model to understand them, and why is this the key to escaping that Gray Zone?