Scientific References

Complete bibliography of evidence-based sources for Cardio Analytics cardiovascular metrics

Clinical Guidelines

  1. Mayo Clinic. What's a normal resting heart rate? https://www.mayoclinic.org/healthy-lifestyle/fitness/expert-answers/heart-rate/faq-20057979
  2. American Heart Association. Understanding Blood Pressure Readings. https://www.heart.org/en/health-topics/high-blood-pressure/understanding-blood-pressure-readings
  3. Cleveland Clinic. Heart Rate Variability (HRV): What It Is and How You Can Improve It. https://my.clevelandclinic.org/health/symptoms/21773-heart-rate-variability-hrv
  4. Mayo Clinic. Low blood oxygen (hypoxemia). https://www.mayoclinic.org/symptoms/hypoxemia/basics/definition/sym-20050930

Peer-Reviewed Research

  1. Perez MV, Mahaffey KW, Hedlin H, et al. Large-Scale Assessment of a Smartwatch to Identify Atrial Fibrillation. N Engl J Med. 2019;381(20):1909-1917. https://www.nejm.org/doi/full/10.1056/NEJMoa1901183
  2. Barrera N, Mahaffey KW, Hedlin H, et al. Accuracy of Smartwatches in the Detection of Atrial Fibrillation: A Systematic Review and Meta-analysis. JACC Advances. 2025;4(1):102133. https://www.jacc.org/doi/10.1016/j.jacadv.2025.102133
  3. Lambe R, Wilkinson M, Barker J, et al. Investigating the accuracy of Apple Watch VO₂ max measurements. PLOS ONE. 2025;20(1):e0323741. https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0323741
  4. Studenski S, Perera S, Patel K, et al. Gait Speed and Survival in Older Adults. JAMA. 2011;305(1):50-58. https://jamanetwork.com/journals/jama/fullarticle/644554 (Open access: PMC)

Apple Documentation & Whitepapers

  1. Apple. Measuring Walking Quality Through iPhone Mobility Metrics. Whitepaper. 2022. https://www.apple.com/healthcare/docs/site/Measuring_Walking_Quality_Through_iPhone_Mobility_Metrics.pdf

Apple Developer Documentation - HealthKit Data Types and Queries

  1. Apple Developer. Resting Heart Rate (restingHeartRate). https://developer.apple.com/documentation/healthkit/hkquantitytypeidentifier/restingheartrate
  2. Apple Developer. Oxygen Saturation (oxygenSaturation). https://developer.apple.com/documentation/healthkit/hkquantitytypeidentifier/oxygensaturation
  3. Apple Developer. Blood Pressure Systolic (bloodPressureSystolic). https://developer.apple.com/documentation/healthkit/hkquantitytypeidentifier/bloodpressuresystolic
  4. Apple Developer. ECG Classification (HKElectrocardiogram.Classification). https://developer.apple.com/documentation/healthkit/hkelectrocardiogram/classification-swift.enum
  5. Apple Developer. Atrial Fibrillation Burden (atrialFibrillationBurden). https://developer.apple.com/documentation/healthkit/hkquantitytypeidentifier/atrialfibrillationburden
  6. Apple Developer. VO₂ Max (vo2Max). https://developer.apple.com/documentation/healthkit/hkquantitytypeidentifier/vo2max
  7. Apple Developer. Walking Speed (walkingSpeed). https://developer.apple.com/documentation/healthkit/hkquantitytypeidentifier/walkingspeed
  8. Apple Developer. Walking Asymmetry Percentage (walkingAsymmetryPercentage). https://developer.apple.com/documentation/healthkit/hkquantitytypeidentifier/walkingasymmetrypercentage
  9. Apple Developer. Stair Ascent Speed (stairAscentSpeed). https://developer.apple.com/documentation/healthkit/hkquantitytypeidentifier/stairascentspeed
  10. Apple Developer. HKAnchoredObjectQuery. https://developer.apple.com/documentation/healthkit/hkanchoredobjectquery
  11. Apple Developer. enableBackgroundDelivery(for:frequency:withCompletion:). https://developer.apple.com/documentation/HealthKit/HKHealthStore/enableBackgroundDelivery(for:frequency:withCompletion:)
  12. Apple Developer. Background Delivery Entitlement. https://developer.apple.com/documentation/bundleresources/entitlements/com.apple.developer.healthkit.background-delivery

Disclaimer

Cardio Analytics does not provide medical diagnosis or treatment. All metrics are for informational purposes only. Always consult a qualified clinician for medical advice, diagnosis, or treatment decisions.

References are provided for educational purposes to explain the scientific basis of cardiovascular metrics. Inclusion of a reference does not imply endorsement by the authors or institutions cited.

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