Imagine checking your blood pressure as easily as glancing at a smartwatch—without the squeeze of a cuff. That future may be closer than we think.
Researchers at Boston University have shown that a light-based technology called speckle contrast optical spectroscopy, or SCOS, can estimate blood pressure more accurately than current cuff-free methods.
High blood pressure, or hypertension, affects nearly half of adults in the United States and is a leading cause of heart disease and stroke.
Traditional cuff-based monitors are effective, but they can be uncomfortable, inconvenient, and not practical for frequent checks.
Many people only have their blood pressure measured during doctor visits, which may not reflect what’s really happening in daily life.
For example, “masked hypertension” occurs when clinic readings look normal but a person’s blood pressure is actually high at home or overnight. Detecting those hidden patterns requires more frequent monitoring.
That’s where SCOS could change the game. SCOS uses safe, noninvasive light to measure blood flow by analyzing the unique speckle patterns created when light bounces off cells and tissue.
Until now, this technique has mostly been used for brain and tissue studies, but researchers wondered if it could also track blood pressure.
In their new study, published in Biomedical Optics Express, the team placed SCOS devices on the fingers and wrists of 30 volunteers.
The devices recorded blood flow and blood volume at rest and during leg press exercises designed to raise blood pressure. These readings were then compared to results from a continuous blood pressure monitor.
The results were impressive. By combining blood flow and blood volume data, SCOS estimated blood pressure up to 31% more accurately than devices that only track blood volume.
This is significant because most optical monitors today—such as those in some smartwatches—rely only on blood volume, also known as photoplethysmography.
SCOS was also able to measure subtle, fast-changing features in blood flow, giving it an edge over existing approaches.
The researchers developed a custom SCOS device using two different laser wavelengths, which allowed them to capture information from multiple tissue depths.
They then used machine learning to analyze the waveforms, or patterns in the data, and predict blood pressure. The system achieved a low average error margin of just 2.26 mmHg for systolic pressure, a level of accuracy that suggests it could be highly useful in real-world settings.
The next challenge is turning the lab device into something wearable. The team plans to shrink its size, improve how data is processed on the device itself, and test its performance during everyday movement.
If successful, SCOS-based wearables could give patients and doctors a much clearer picture of cardiovascular health, helping to catch problems earlier and make treatment more effective.
For millions living with or at risk of hypertension, this could mean a more comfortable and reliable way to keep track of one of the body’s most important vital signs.
