Heart Rate Zone Calculator

Training by heart rate is popular because the same effort changes with heat, sleep, and caffeine, but a zone still lands you in a broad band. Enter a max and resting HR (or a field-test pair), and read zones as percent of reserve, which tracks fitness better than max alone. Always listen to your body, doctor, and actual lab tests before pushing into high zones that feel wrong.

[calculator id="heart-rate-zone-calculator"] — Shortcode reference; the live calculator mounts in the block below when the child theme enqueues the matching script.