top of page
Search

Smart Rings for Cuffless Blood Pressure Monitoring: Insights from a First-in-Human Clinical Study


Published Research:First-in-Human Study for Evaluating the Accuracy of Smart Ring-Based Cuffless Blood Pressure Measurement🔗 Full Study Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC10789523/


Authors & Institutions:Conducted by researchers from Seoul National University Hospital (SNUH) in collaboration with Sky Labs Inc., South Korea.


Introduction

Blood pressure monitoring has traditionally relied on arm cuffs — devices that are bulky, uncomfortable, and not suited for continuous daily monitoring. With cardiovascular diseases rising globally, new technologies are urgently needed for easier, more accessible blood pressure tracking.

A groundbreaking first-in-human study by Seoul National University Hospital and Sky Labs Inc. investigates whether a smart ring can accurately measure blood pressure without a cuff, using optical and algorithmic sensing.This report marks a major milestone in the evolution of wearable health technology.



The Device: CART-I Plus Smart Ring

Developed by Sky Labs Inc., the CART-I Plus smart ring uses photoplethysmography (PPG) and proprietary algorithms to estimate blood pressure.

It measures:

  • Systolic Blood Pressure (SBP)

  • Diastolic Blood Pressure (DBP)

  • Heart rate

  • Pulse waveform

  • SpO₂ (oxygen saturation)

  • ECG signals

Worn like a normal finger ring, it offers continuous, comfortable, cuffless BP monitoring.


Study Design & Methodology


The clinical study took place at Seoul National University Hospital, using a prospective comparative design.

Participants underwent multiple BP measurements:

  1. Using the smart ring on a finger

  2. Using a standard upper-arm cuff device (auscultatory method — the clinical gold standard)

Participants & Data

  • 89 volunteers

  • Over 500 paired measurements

  • Included wide BP ranges (low, normal, elevated, hypertensive)

The goal was to compare the ring’s BP readings with the standard cuff device to evaluate accuracy, reliability, and clinical validation.


Key Results


1. Strong Correlation With Standard BP Measurements

  • SBP correlation: r = 0.94

  • DBP correlation: r = 0.95

These values indicate very high agreement between the smart ring and traditional cuff-based methods.


2. Accuracy Within Clinical Standards

Percentage of smart ring readings close to the standard reference:

  • 67% within ±5 mmHg (SBP)

  • 76% within ±5 mmHg (DBP)

  • Over 90% within ±10 mmHg

This level of accuracy is considered acceptable for clinical validation studies.


3. Reliable Across Different BP Levels

Performance remained consistent across low, normal, and high BP categories.


Why This Study Matters

Continuous, Real-Life BP Monitoring

Unlike cuff devices, a smart ring enables:

  • 24/7 monitoring

  • Sleep BP tracking

  • Early detection of hypertension trends

  • Better long-term health insights


Perfect for Remote & Preventive Healthcare

Ideal for:

  • Chronic disease management

  • Telemedicine

  • Home-based BP monitoring

  • Elderly care

  • Fitness & wellness tracking


Comfort and Ease of Use

No arm squeezing.No setup.No interruption of daily activities.


Limitations Acknowledged by Researchers

  • Larger multi-ethnic cohorts needed

  • Long-term daily wear performance to be evaluated

  • Physiological differences between finger and arm BP require further modeling

Despite these, the findings strongly support the feasibility and accuracy of cuffless smart ring BP monitoring.


Conclusion

The collaborative study by Seoul National University Hospital and Sky Labs Inc. confirms that smart rings can accurately measure blood pressure without a cuff, opening the door to the next generation of continuous, wearable health monitoring.


This technology has the potential to transform hypertension management and everyday wellness tracking — making blood pressure monitoring more accessible, comfortable, and data-rich than ever before.

 
 
 

Comments

bottom of page