Readiness, Recovery, and Strain Scores

Consumer wearables roll several signals into headline scores:

• Readiness / Recovery score — "how recovered are you today" as a percentage or 0–100. The most common inputs are HRV (the heaviest contributor), resting heart rate, sleep duration/quality, respiratory rate, skin temperature, and recent training load, each compared to your personal baseline rather than a universal standard. (See hrv, resting-heart-rate, sleep-tracking.)
• Strain score — "how much stress you've put on the body today," driven mainly by heart-rate-derived load over the day/session. One popular platform uses a 0–21 strain scale based on the Borg perceived-exertion concept.

The intended loop: high readiness/recovery → green light for hard training; low → ease off or recover. Strain is then balanced against recovery so you train hard when recovered and pull back when not (a form of autoregulation-rpe-rir).

Critical limits — treat scores as directional, not gospel:

• Proprietary and opaque. Each brand's algorithm differs and is undisclosed, so scores aren't comparable across devices and can't be independently validated. Research evaluating these composite scores finds them inconsistent.
• Baseline-relative. A "70%" means relative to your recent norm, not an absolute health statement.
• Garbage-in. They inherit sensor error, especially wrist-optical HRV/HR (see hr-monitor-accuracy, wearable-accuracy-limits).
• They miss life. A score can read "recovered" while you feel awful, or vice versa.

Use them alongside your own subjective ratings and training-load picture (see training-load-monitoring); when score and feel disagree, weight how you feel and the trend, not a single day's number. A sustained low-recovery run is a real flag (see overtraining-overreaching).

• Readiness/recovery blend HRV (top input) + RHR + sleep + resp rate + skin temp + load.
• Scores are computed vs your personal baseline, not an absolute scale.
• Strain ≈ daily HR-derived load; one platform uses a 0–21 Borg-based scale.
• Algorithms are proprietary, brand-specific, not cross-comparable or independently validated.
• Directional nudges only — don't override how you feel; pair with subjective ratings.

• hrv — the heaviest-weighted score input.
• resting-heart-rate — core score input.
• readiness-self-assessment — subjective cross-check on the score.
• training-load-monitoring — strain is the load side of the loop.
• autoregulation-rpe-rir — scores feed (but shouldn't dictate) training decisions.