HRV + sleep
Uses recovery signals from Apple Health to separate normal fatigue from real readiness drag.
Ruck Mode reads HRV, sleep, resting heart rate, and recent load to give trail runners one useful answer: send it, go steady, or ease up.

Uses recovery signals from Apple Health to separate normal fatigue from real readiness drag.
Recent volume and effort influence the verdict so a hard week does not look like a fresh day.
Elevation and long-run history make the score more useful for outdoor athletes.