Why Your Zone 2 Is Probably Wrong

The Issue: The Flawed Definition of Zone 2 You’ve heard it a hundred times: to run faster, you need to run slower. Zone 2 training is everywhere.

But here is the uncomfortable truth: the Zone 2 you think you’re running is probably not Zone 2 at all. We typically define Zone 2 in two ways.

First, as a percentage based on age formulas like “220 minus your age.” Second, through the subjective “Talk Test” — running at a comfortable intensity where you can hold a conversation.

Neither of these captur...