Why your heart rate in zone 2 sometimes tells you almost nothing
In the easy range your heart rate responds flatly and slowly, and it creeps up on its own through cardiac drift. Why a zone boundary says little there — and what to steer by instead.
Guide
Each article answers one question about heart rate, thresholds and recovery: what the number means and what you can do with it.
What is LT1, and how do you measure it without a lab?
LT1 is your aerobic threshold: the top of your genuinely easy endurance work, below your threshold heart rate (LT2). How to approach it with the talk test, the drift method and your own sessions.
Looking for the short explanation of a single term? That lives in the glossary.