Medical Disclaimer

1. Not a Medical Device

MARCWILLS HRVA has not been evaluated, cleared, or approved by any medical regulatory authority (including but not limited to the FDA, CE, or BPOM) as a medical device. The App must not be used as a substitute for professional medical equipment, clinical-grade ECG devices, or regulated health monitoring systems.

2. No Clinical Validation

The heart rate variability (HRV) metrics and physiological data produced by this App have not been validated against clinical-grade ECG or other gold-standard medical measurement methods. While the App uses a Polar H10 chest belt sensor — a device used in many sport science research contexts — the outputs of this App should not be treated as clinically validated measurements.

3. Not a Substitute for Medical Advice

The data, metrics, and reports generated by this App do not constitute medical advice. Always consult a qualified and licensed healthcare professional for:

• Diagnosis of any medical condition
• Interpretation of cardiovascular or physiological data in a clinical context
• Treatment decisions or therapeutic interventions
• Assessment of fitness for physical activity in individuals with known or suspected health conditions

4. Intended Audience

This App is designed for use by:

• Sport science researchers and exercise physiologists
• Coaches and athletic trainers
• Academics and students in health-related disciplines
• Wellness-conscious individuals with a basic understanding of HRV concepts

It is not designed for use in emergency situations, intensive care, or any life-critical monitoring context.

5. Sensor Limitations

The App acquires data via a Polar H10 chest belt sensor using Bluetooth Low Energy. While the Polar H10 is widely used in sport science research, it is not a medical-grade ECG device. Signal quality may be affected by:

• Improper sensor placement or poor electrode contact
• Motion artifacts during physical activity
• Electromagnetic interference
• Individual physiological variation
• Ectopic beats and arrhythmias that may not be correctly handled

6. HRV Analysis Limitations

Heart rate variability analysis has inherent limitations that users must understand:

• HRV metrics require minimum 5 minutes of stationary recording for valid frequency-domain analysis (Task Force ESC/NASPE, 1996)
• Time-domain HRV metrics (RMSSD, SDNN) are degraded during physical activity and should be interpreted with caution in Activity Mode
• Frequency-domain metrics (LF, HF, LF/HF, Total Power) are only valid under stationary, resting conditions
• Individual baseline differences mean that absolute HRV values cannot be interpreted without individual reference data

7. Emergency Situations

Do not use this App in emergency situations. If you or a research subject experience chest pain, shortness of breath, irregular heartbeat, loss of consciousness, or any other medical emergency:

• Stop using the App immediately
• Call emergency services (119 in Indonesia, or local equivalent)
• Seek immediate medical attention

8. Limitation of Liability

The developer (Kukuh Pambuka Putra) makes no representations or warranties regarding the accuracy, reliability, or fitness for a particular purpose of any measurement or output produced by this App. To the maximum extent permitted by applicable law, the developer shall not be liable for any harm, injury, or adverse outcome arising from reliance on the App's outputs.

9. Governing Reference

HRV analysis methodology in this App is based on:

• Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology (1996). Heart Rate Variability: Standards of Measurement, Physiological Interpretation, and Clinical Use. Circulation, 93(5), 1043–1065.
• ACSM Guidelines for Exercise Testing and Prescription (Karvonen intensity zones)

Contact

For questions about this disclaimer, contact:
Kukuh Pambuka Putra
Developer, MARCWILLS
Email: kukuh.pambuka@outlook.com