Samsung Galaxy Watch BioActive Sensor
Samsung Galaxy Watch 7 and Ultra use the BioActive Sensor 3.0, a multi-wavelength PPG system combining optical heart rate (green, red, infrared LEDs), electrical body composition analysis (BIA), and electrocardiogram (ECG) in a single sensor unit. This integration enables blood pressure estimation through PTT and multi-parameter cardiovascular monitoring.
The BioActive Sensor 3.0 integrates three sensor modalities: optical PPG with five LEDs (green 523 nm ×4, infrared 1050 nm ×1) and five photodiodes for heart rate and SpO2; bioelectrical impedance analysis (BIA) electrodes for body composition; and ECG electrodes for single-lead rhythm recording. The combined ECG+PPG measurement enables precise PTT calculation as the delay between the ECG R-peak and the PPG systolic foot — the most accurate method for cuffless BP estimation as it eliminates pre-ejection period confounds when using pure PPG timing.
Samsung's Blood Pressure feature (available in Korea and some European markets, pending FDA clearance in the US) uses a calibration protocol where the user measures BP with a standard arm cuff, then the watch calibrates its PTT-to-BP transfer function personalized to that individual. Samsung guidelines recommend monthly recalibration to maintain accuracy. Published validation data from the Samsung Medical Center showed mean error of -3.1 ± 8.3 mmHg for systolic BP and -0.1 ± 7.2 mmHg for diastolic BP in 45 participants — meeting ISO 81060-2 criteria in this controlled study. Independent replication studies show less consistent results.
The Body Composition feature uses BIA (four-frequency, 15–1000 kHz) to estimate skeletal muscle mass, body fat percentage, visceral fat, and total body water. Validation against DEXA shows mean error of ±2.3% for body fat percentage. The integration of BIA with PPG enables more sophisticated cardiovascular risk assessment by combining functional (blood pressure, HRV) and structural (body composition) biomarkers in a single device.
Frequently Asked Questions
Is Samsung Galaxy Watch blood pressure FDA approved?
Samsung Blood Pressure monitoring is not FDA cleared in the US as of 2025. It is CE-marked in Europe and available in South Korea and some other markets. Samsung continues FDA clearance discussions. The feature requires monthly recalibration and is not indicated for clinical diagnosis.
How does Samsung's ECG compare to Apple Watch ECG?
Both use single-lead (Lead I) ECG recorded between left wrist and right index finger contact. AF detection accuracy is comparable (AUC 0.97–0.99 in controlled studies). Samsung Galaxy Watch ECG is FDA cleared (510(k) K203346). Key difference: Samsung requires touching the side bezel; Apple uses the Digital Crown.
What is the BioActive Sensor 3.0 sampling rate?
PPG sampling rate is reported as 25 Hz for continuous background monitoring and higher rates during explicit measurements. ECG samples at 500 Hz for rhythm analysis. BIA measurement is a spot-check mode requiring 10-second stationary measurement.