{ "registry": "KnowYourPrime Evidence Registry", "license": { "name": "CC BY 4.0", "url": "https://creativecommons.org/licenses/by/4.0/", "attribution": "Credit KnowYourPrime and link to the finding URL." }, "fields": { "devices": "Devices this finding names, including models it says it does not cover. What was actually tested is in scope.applies_to; exclusions are in scope.does_not_cover.", "evidence": "Studies by role: anchor (the rating rests on it), conflicting, null_result, supporting.", "industry_ties": "Device-maker ties listed in Europe PMC metadata: author_affiliations names makers an author lists as an affiliation, funders names makers listed as funding. stated_ties holds ties a paper states only in its own conflict, funding or acknowledgement text, each read from that statement and worded to say only what it says. Sources are Europe PMC metadata, funding printed in the abstract, and those reviewed statements. An empty list means no tie was found there, not that the study is independent: many papers have no open full text to read. Metadata, not a judgment of the study. checked false means no Europe PMC metadata was available." }, "id": "KYP-ER-0005", "version": "1.0", "reviewed": "2026-10-24", "url": "https://knowyourprime.com/evidence-readiness-recovery-score-validity", "title": "Readiness and Recovery Score Validity", "question": "Do consumer wearable readiness and recovery scores, and the overnight heart measurements behind them, measure what they claim accurately?", "measurement": "Readiness and recovery scores", "devices": [ "Oura", "WHOOP", "Garmin", "Polar", "Fitbit", "Samsung", "Ultrahuman", "Amazfit", "Suunto", "Coros", "Withings" ], "rating": { "label": "Uncertain", "code": "uncertain", "definition": "Evidence is conflicting, inconsistent, or difficult to interpret.", "rule_version": "1.6", "rule_reasons": [ "An anchor study was assessed but it does not test this claim’s core relationship directly, so the evidence is treated as unsettled rather than affirming.", "An anchor study was assessed but its own reported finding supports this claim only weakly, so the evidence is treated as unsettled rather than affirming.", "Some evidence conflicts on secondary points that do not change the core direction." ] }, "conclusion": "The scores themselves have not been validated. No manufacturer publishes its formula, few offer empirical evidence for their scores, and the overnight heart rate and HRV inputs are accurate on some devices and not others.", "reasoning": [ "A readiness or recovery score is a proprietary composite, usually built from overnight HRV, resting heart rate, sleep and recent activity. Two things would have to hold for it to mean what it says: the inputs would have to be measured accurately, and the combination would have to track a real state such as recovery or strain.", "The most comprehensive review of the scores found no manufacturer disclosed its algorithm and few provided empirical or peer-reviewed validation. The best head-to-head study of the overnight inputs found two devices close to ECG and two well short. Neither anchor cleanly affirms the claim, so the rule rates it Uncertain." ], "key_results": [ { "text": "A review of 14 composite scores from 10 manufacturers, including Oura Readiness and Resilience, WHOOP Recovery and Strain, Garmin Body Battery and Training Readiness, Fitbit Daily Readiness, Samsung Energy Score and Ultrahuman Dynamic Recovery, found none disclosed its exact formula and few provided empirical validation.", "source": "doi:10.1515/teb-2025-0001", "source_url": "https://doi.org/10.1515/teb-2025-0001", "source_citation": "Doherty et al., Translational Exercise Biomedicine, 2025" }, { "text": "The same review found HRV in 86 percent of the scores, resting heart rate in 79 percent, and physical activity and sleep duration in 71 percent each, with different time windows and weightings.", "source": "doi:10.1515/teb-2025-0001", "source_url": "https://doi.org/10.1515/teb-2025-0001", "source_citation": "Doherty et al., Translational Exercise Biomedicine, 2025" }, { "text": "For the overnight inputs, Oura Gen 3 and Gen 4 reached resting heart rate concordance of 0.97 and 0.98 with ECG and WHOOP 0.91, against 0.86 for Polar; Garmin was excluded from that analysis for methodological inconsistencies.", "source": "doi:10.14814/phy2.70527", "source_url": "https://doi.org/10.14814/phy2.70527", "source_citation": "Dial et al., Physiological Reports, 2025" } ], "scope": { "applies_to": "Proprietary readiness, recovery, strain and energy scores from consumer wearables, and the accuracy of the overnight heart rate and HRV they are built on.", "does_not_cover": "Whether any score predicts injury, illness, performance, burnout or a workplace outcome, which no independent study scored here has tested; Apple Watch Readiness, introduced in September 2026 after these studies." }, "limitations": [ "Only five studies are scored, and two of them are letters about how wearable comparisons are reported.", "Because the formulas are unpublished, a validation of one score does not carry to another, or to the same score after an update." ], "evidence": { "anchor": [ { "key": "doi:10.1515/teb-2025-0001", "title": "Readiness, recovery, and strain: an evaluation of composite health scores in consumer wearables", "first_author": "Doherty", "journal": "Translational Exercise Biomedicine", "year": 2025, "url": "https://doi.org/10.1515/teb-2025-0001", "industry_ties": { "checked": false } }, { "key": "doi:10.14814/phy2.70527", "title": "Validation of nocturnal resting heart rate and heart rate variability in consumer wearables.", "first_author": "Dial", "journal": "Physiological reports", "year": 2025, "url": "https://doi.org/10.14814/phy2.70527", "industry_ties": { "checked": true, "author_affiliations": [], "funders": [], "stated_ties": [] } } ], "supporting": [ { "key": "doi:10.1016/j.archger.2026.106306", "title": "Validity and reliability of smartwatch-based upper-extremity function and heart rate assessment in outpatient older adults.", "first_author": "Hosseinalizadeh", "journal": "Archives of gerontology and geriatrics", "year": 2026, "url": "https://doi.org/10.1016/j.archger.2026.106306", "industry_ties": { "checked": true, "author_affiliations": [], "funders": [], "stated_ties": [] } } ] }, "evidence_last_evaluated": "Oct 15, 2026", "rating_history": [ { "date": "2026-07-20", "rating": "Emerging", "from": null, "rule_version": "1.4" }, { "date": "2026-10-02", "rating": "Uncertain", "from": "Emerging", "rule_version": "1.6" } ], "versions": [ { "version": "1.0", "date": "2026-10-24", "rating": "Uncertain", "change": "First published." } ], "research_desk": "https://knowyourprime.com/research-desk-recovery#measurement-validity", "related_findings": [ "https://knowyourprime.com/evidence-wearable-hrv-accuracy", "https://knowyourprime.com/evidence-work-stress-hrv" ], "related_articles": [ "https://knowyourprime.com/are-recovery-and-readiness-scores-validated", "https://knowyourprime.com/how-reliable-is-recovery-score-day-to-day", "https://knowyourprime.com/recovery-score-vs-readiness-score", "https://knowyourprime.com/do-workplace-wellness-programs-work" ], "methodology": "https://knowyourprime.com/methodology", "citation": "KnowYourPrime Evidence Registry, Finding KYP-ER-0005, version 1.0, reviewed 2026-10-24. https://knowyourprime.com/evidence-readiness-recovery-score-validity" }