Wearable health devices are evolving rapidly, but the technology behind them can be confusing. Two of the most common heart-monitoring methods are PPG (Photoplethysmography) and ECG (Electrocardiography). Understanding the difference helps you choose the right device for your needs. In this guide, we’ll break down the science, accuracy, and applications of both—and explain why Doni Ring’s PPG technology stands out in smart rings.
1. What Is PPG?
PPG (Photoplethysmography) is an optical method that measures blood volume changes in the microvascular tissue beneath the skin.
How it works:
- The sensor emits light (usually green LEDs) into the skin.
- Blood absorbs light differently depending on the pulse.
- The sensor detects the reflected light, creating a signal that represents heart rate and other metrics.
Advantages:
- Non-invasive and compact, ideal for smart rings.
- Can track heart rate, blood oxygen, stress, and sleep patterns continuously.
- Low power consumption, allowing multi-day battery life.
Limitations:
- Sensitive to motion artifacts (e.g., typing or exercise).
- Provides a trend or estimate rather than full clinical diagnostics.
2. What Is ECG?
ECG (Electrocardiography) measures the electrical activity of the heart directly.
How it works:
- Electrodes detect electrical signals generated by heartbeats.
- The data can be displayed as an ECG waveform, showing P, QRS, and T waves.
Advantages:
- High accuracy for detecting arrhythmias, AFib, or heart abnormalities.
- Clinically validated and often used in medical settings.
Limitations:
- Usually requires specific electrode placement (more suitable for chest straps, smartwatches, or dedicated ECG patches).
- Less convenient for continuous all-day wear in ring form.
3. PPG vs ECG: Key Differences
| Feature | PPG | ECG |
|---|---|---|
| Measurement | Optical (blood volume changes) | Electrical (heart activity) |
| Accuracy | High for heart rate trends, moderate for clinical-level diagnosis | Very high for arrhythmias & heart condition detection |
| Form Factor | Small, ideal for rings and wristbands | Larger, requires electrodes & proper placement |
| Continuous Monitoring | Yes | Limited by convenience & comfort |
| Applications | Fitness, stress, sleep, hormone monitoring | Clinical diagnosis, arrhythmia detection |
4. Why PPG Works Well in Smart Rings
Smart rings like Doni Ring are designed for continuous, unobtrusive wear. PPG sensors allow:
- High-precision tracking with self-developed sensor arrays
- Medical-grade algorithms for blood pressure and heart rate analysis
- Real-time waveform display for more actionable insights
- Comfort, discretion, and multi-day battery life
While ECG is excellent for clinical evaluation, PPG provides a practical balance of accuracy, convenience, and versatility for everyday health monitoring.
Conclusion
PPG and ECG are both powerful technologies, but their use cases differ. PPG is ideal for compact wearables like smart rings, while ECG excels in clinical or medical-grade monitoring. Doni Ring leverages advanced PPG technology to offer medical-grade trends, blood pressure waveform visualization, and continuous tracking—all in a sleek, comfortable ring.
