Zone 2 training explained (and why everyone is talking about it)

Zone 2 training — steady, easy aerobic work — went from coaching secret to internet obsession. The hype is mostly justified. Here is what it is and how to use it.

What Zone 2 is

Zone 2 is a low-intensity effort you can sustain for a long time while still holding a conversation. Physiologically it is the effort just below where lactate starts to rise — the sweet spot for building aerobic capacity and fat metabolism.

Why it works

Training in Zone 2 develops the adaptations that underpin endurance: mitochondrial density, capillarisation and the ability to burn fat for fuel. It builds the engine without the fatigue cost of hard intervals, so you can do a lot of it. It is the backbone of base training.

How to find your Zone 2

Roughly 60–70% of max heart rate, or the pace where you can still speak in full sentences but would rather not. If you have tested your FTP or threshold, Zone 2 sits well below it. The talk test is surprisingly reliable.

How much do you need?

For most endurance athletes, the majority of weekly volume should be Zone 2, with a smaller dose of high intensity — the classic polarised approach. Track your load so easy stays easy and fatigue stays in check. TrainCurve does it automatically — start free.