Heart rate threshold
From the app’s English Help & Guide · Reference release 1.0.19
What Metered estimates
Metered uses the Workwell Foundation starting point of resting heart rate + 15 BPM as a practical pacing estimate. POTS profiles use a tighter default of resting + 10 BPM.
How to use it
The threshold appears in the health strip when Apple Watch heart-rate data is available. Activity timer pacing alerts are separate and session-only: start a planned activity with pacing enabled and Metered suggests resting HR + 20 BPM, adjustable by 10 BPM.
Important limits
This is not a measured anaerobic threshold and it cannot guarantee PEM prevention. Treat it as a conservative planning cue, then adjust with your own symptoms and clinician advice.