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?

You know the drill: it is Sunday morning, the sun is shining, and you have a targeted 90-minute Zone 2 training session scheduled. Just spinning the legs, keeping your heart rate or power strictly within the lines. The goal? To train your fat oxidation and build that unshakeable aerobic base.

But then, halfway through, that steep railway bridge appears. Your cycling ego starts to tickle. You push through, click into a heavier gear – and bam, you fly up. Heart rate and power skyrocket out of their tight boxes. Reaching the top, you ease off the pedals, your breathing calms down, and your watch quickly signals you are right back in Zone 2.