Here’s a general explanation (and a few caveats) about how a watch like your BUDDI watch from Vitalfriend.com might “read” blood pressure and what that really means.
How it likely works: estimations via sensors, not a cuff
Many modern “BP-watch” or “smartwatch” devices don’t inflate a cuff the way a traditional blood pressure monitor does. Instead, they rely on optical sensors often using a method called Photoplethysmography (PPG). That means the watch shines a light into your wrist and measures how blood flows under the skin as your heart beats. Wikipedia+2YOLO+2
The watch then uses advanced algorithms to estimate your blood pressure based on the characteristics of those blood-flow signals (pulse wave shape, timing, volume changes, etc.). Some devices also combine this with user info (age, sex, weight, etc.) to improve estimates. Reddit+2PMC+2
Sometimes these watches use a method tied to something called Pulse Transit Time (PTT) or related pulse-wave analysis: that’s a calculation of how long it takes the pressure wave from your heartbeat to travel through your arteries to the wrist. The theory: arterial stiffness or higher pressure affects that travel time which can be linked to blood pressure. Reddit+2Harvard Health+2
Why these readings are approximate and not like a traditional BP cuff
According to recent research and reviews, these “cuffless” wearables do not (yet) match the accuracy and reliability of standard cuff-based monitors. Nature+2PMC+2
Most experts say that such devices can detect relative changes (i.e. “your pressure seems higher than usual” or “lower than before”) more reliably than delivering an accurate absolute blood pressure number. Consumer Reports+2Reddit+2
Because of that, in many cases those BP-watch readings should be taken with caution, especially if you're using them to make health decisions (medication, diagnosing hypertension, etc.). Medical guidelines still favor cuff-type upper-arm monitors for accurate BP tracking. Cleveland Clinic+2Mayo Clinic+2
Also, if the watch requires calibration (some watches + apps ask you to “calibrate” by inputting a reading from a traditional cuff initially), then periodic recalibration is needed to maintain reasonable estimates. Consumer Reports+2Medical Device Network+2
What that means for your reader: what the BUDDI watch can and can’t tell them
The BUDDI watch can approximate your blood pressure, it may track trends (when your pressure seems to go up or down) rather than always giving a perfectly accurate number.
It might be more useful for getting a sense of fluctuations (for example: “My BP seems elevated after exercise / stress / late night”) rather than replacing a cuff-based BP monitor entirely.
If your reader wants precise BP for health monitoring (especially if there’s hypertension risk, heart conditions, or similar), it’s safer to use a traditional validated BP monitor or have regular clinical checks.
What research says about cuffless BP-watch accuracy
✅ Some studies show reasonably good agreement (in limited settings)
A recent 2025 review found that a smartwatch-type BP monitor (similar to cuffless wrist devices) produced BP readings within about 5 ± 8 mmHg of a reference (cuff-based) device, in both static (sitting) conditions and during light exercise. Nature
A systematic review / meta-analysis (2022) compared 15 cuffless wearable BP devices (using mostly photoplethysmography, PPG) and found that, on average, the bias (difference) in systolic BP (SBP) and diastolic BP (DBP) compared with reference devices was modest: pooled mean difference of about +3.4 mmHg (SBP) and +1.2 mmHg (DBP). OUP Academic
Some individual smartwatch-based BP-measurement studies reported that when properly calibrated watch BP readings roughly matched a conventional BP monitor. Cardiology Research+2ResearchGate+2
A 2025 study even found that a smartwatch combining PPG + ECG sensors produced accurate and reliable BP measurements in patients with acute ischemic stroke. LWW Journals
So in certain contexts (resting, controlled environment, calibration done), cuffless BP watches can come surprisingly close to standard cuff-based readings.
But many studies show important limitations / lack of reliability especially under real-world or varying conditions
A 2022 study concluded that a consumer-grade smartwatch using cuffless BP estimation “demonstrates insufficient accuracy” for clinical BP measurement. PMC+1
The same 2022 study (on a popular smartwatch) showed systematic bias: low blood pressures tended to be overestimated, high pressures underestimated. That means these devices do not reliably track extremes. Frontiers
A 2025 systematic review comparing continuous wearable cuffless BP devices against conventional 24-hour ambulatory BP monitoring (ABPM) found that while daytime BP readings were comparable (mean differences within acceptable range), night-time BP readings had notable discrepancies (under/over-estimation). PMC+1
One validation study of a low-cost smartwatch found it not suitable for daily BP monitoring (and also failed for oxygen saturation), although it performed well for heart rate. MDPI
Experts stress that for now, the BP values from cuffless wrist devices are not recommended for clinical use, because there is no universally accepted standard to validate them. Nature+2Medical Device Network+2
Additional real-world challenges: wrist-based (or wristband) readings are highly sensitive to positioning, movement, and calibration. For example, raising/lowering the wrist from heart level or having the strap too loose can cause inaccurate readings. Mayo Clinic+2Consumer Reports+2
What this means in practice (for watches like BUDDI)
Your BUDDI watch if it uses similar technology (optical sensors / PPG or other pulse-wave analysis) could under ideal conditions give BP estimates that are reasonably close to an actual BP cuff reading (within a few mmHg).
It’s more likely to be “good enough” for tracking general trends (e.g., “my BP seems higher today than yesterday,” or “my BP rises after stress/exercise”) rather than giving a fully reliable, clinically accurate BP reading every time.
Readings may become unreliable if you move, change wrist position, or don’t calibrate properly. Night-time or sleep BP estimates seem especially error-prone.
For critical health decisions (medication adjustments, diagnosing hypertension, etc.), a validated upper-arm cuff-based monitor or professional clinical measurement remains the gold standard.
Bottom Line: Promising for convenience & trend-tracking, but not yet a full substitute for a cuff
Cuffless BP watches like BUDDI are improving. Recent studies suggest they can approximate real BP under some conditions. But limitations still remain particularly under everyday, dynamic situations or when trying to capture precise BP values (especially at night or extremes).
Examples of (Relatively) Validated / Approved BP-Measuring Wearables
Below are some of the watches or wearables with the strongest validation / regulatory backing (or with published peer-reviewed validation studies):
Wellue / Vitalfriend Smart Blood Pressure Watch with Micro Aircuff - This is a “micro-aircuff” watch, meaning it uses an inflatable mechanism more akin to a traditional cuff rather than pure optical sensor estimation. That tends to lead to more accurate readings compared to cuffless, PPG-only devices.
YHE BP Doctor Med Smartwatch and YHE BP Doctor Pro Smartwatch- Among the wearable BP-monitors marketed as “medical-grade.” Their claims suggest they aim for blood pressure measurement rather than just trend estimates. That said, I did not find robust publicly available peer-review studies (in major journals) that confirm they meet internationally accepted BP-device validation protocols (like ISO 81060-2). So treat with caution.
Cn-Meditech BP Smartwatch and Poalarhealth PH70 Smart Watch - Similar “wrist BP watch” devices; usually inflated-cuff or micro-cuff design. As with other non-major-brand devices, independent peer-review data is scarce or not publicly available.
YHE S7 Ultra Blood Pressure Smartwatch - Another option among newer watches claiming BP tracking. Because this market is evolving quickly, it’s not yet clear whether long-term, peer-reviewed validation studies support their claims.
Withings ScanWatch Vitals - While this hybrid smartwatch is strong at health metrics (heart rate, sleep, activity, ECG, etc.), evidence and user-community discussion suggest it does not reliably measure blood pressure (or at least it isn’t marketed primarily as a validated BP monitor). Reddit+1
Samsung Galaxy Watch7- Like many “fitness-smartwatches,” it may offer BP estimation (via PPG or pulse-wave methods), but these tend to be unvalidated for medical-grade BP reading. Independent studies of earlier Galaxy watches found BP estimations insufficient for clinical use. PubMed+1
Best-Documented / Published Validation: Huawei / Huawei Watch D Series (built-in oscillometric cuff)
One of the strongest cases among wrist-worn devices is Huawei Watch D (and the later Watch D2):
A 2022 study of Watch D showed that its oscillometric wrist BP measurements met the internationally accepted standard (AAMI/ESH/ISO 81060-2:2018) for accuracy, mean difference vs reference: 1.4 ± 6.47 mmHg (systolic), −0.2 ± 5.85 mmHg (diastolic). Ovid+2OUCI+2
Another ambulatory / rest + 24-hour BP validation of the updated Watch D2 also reported good agreement vs conventional ambulatory BP monitors: for resting, the difference was about −1.6 ± 6.4 / −1.9 ± 5.0 mmHg (systolic/diastolic) using the standardized protocol. PubMed+1
According to the authors, when used properly (wrist at heart level, following instructions for use), Watch D can be “recommended for self-measurement.” Cardiology Research+1
→ This means among wrist-worn devices that inflate a cuff (miniaturized oscillometric cuff) rather than rely on pure PPG estimation there are devices that have passed rigorous validation.
What “Validated / Approved” Means and Why Most Smartwatches Still Fall Short
Validation standards: The widely accepted standard for medical-grade BP monitors is from ISO 81060-2 (plus protocols by AAMI/ESH). Devices that meet these have been tested in controlled settings (resting, multiple BP ranges, adequate sample size) and compared against reference sphygmomanometers. Ovid+2PubMed+2
Oscillometric vs PPG: The devices that meet these standards are usually those using an actual cuff (even if micro or wrist-based) because oscillometric measurement is more directly comparable to classic arm-cuff sphygmomanometers. Purely optical (“cuffless”) devices using PPG or pulse-wave algorithms remain far harder to validate across populations, motion states, wrist sizes, etc. Several experts recommend continuing to rely on cuff-based monitors until more robust validation is widespread. UW Medicine | Newsroom+2ama-assn.org+2
Context matters: Even with validated wrist-cuff devices, accuracy depends on correct usage proper strap tightness, positioning the wrist at roughly heart level, staying still during measurement. For purely PPG-based devices, movement, wrist posture, skin tone, and other variables can degrade accuracy considerably. Cardiology Research+2Cardiology Research+2
What This Means for You & Readers (and Watches Like Your BUDDI)
There are wrist-worn blood pressure watches on the market that have undergone independent validation under accepted international standards e.g., Huawei Watch D / Watch D2. If you’re serious about relatively accurate BP readings from a wearable, these are among the more credible options today.
Many other “BP smartwatches” (especially those relying on PPG / optical sensors, or marketed for “wellness”) still lack wide peer-review validation. Their readings may at best be useful for general trends, not for diagnosing or making medical decisions.
If you or your readers rely on BP data for health e.g. high blood pressure, medication adjustments validated oscillometric-cuff devices remain the safest, most reliable choice. Cuffless watches are still an “emerging tech,” not yet a full substitute.
I checked as of late 2025, there are a small number of wrist-worn / watch-style devices on the market that have undergone independent validation (or regulatory clearance) for blood pressure measurement but the list is still very limited. Below is a summary of the ones that meet recognized validation or regulatory-authorization standards, followed by the caveats.
Wrist / Watch-style BP Devices with Independent Validation or FDA Clearance
Here are some of the most credible wrist-based blood-pressure devices currently available that have evidence or regulatory approval behind their BP-measurement claims:
Wellue Smart Blood Pressure Watch with Micro Aircuff- This watch uses an oscillometric micro air-cuff, not just optical sensors. According to the manufacturer, it is “medical-grade” and FDA-cleared / CE-certified, which places it among the more trusted wrist-based BP devices. Wellue
Omron 3 Series Wrist Blood Pressure Monitor (BP6100) - This is a traditional wrist-cuff BP monitor (not a “smartwatch”). It appears on validated device lists when properly used (correct positioning, wrist at heart level, etc.). Validate BP
Omron HCR6900T Series Wearable Blood Pressure Monitor - A more premium wearable from a recognized BP-device manufacturer. As a wearable designed for BP measurement, it’s among the more credible “watch-style” options (though it’s more “medical wearable” than “smartwatch”).
YHE BP Doctor Pro Smartwatch - Marketed as a “medical-grade wearable blood pressure smartwatch.” That said, I did not find independent peer-review published studies validating it according to recognized standards (e.g. ISO 81060-2), so treat claims with caution.
Withings BPM Connect Blood Pressure Monitor, Beurer Wrist Blood Pressure Monitor, HealthSmart Premium Wrist Digital Blood Pressure Monitor, and Homedics 700 Series Wrist Cuff Blood Pressure Monitor - These are wrist-cuff BP monitors (not necessarily “smartwatches”). Wrist-cuff monitors can be validated and used legitimately for home BP measurement if used correctly (proper cuff placement, wrist position, etc.), though in clinical practice upper-arm cuffs remain preferred. Validate BP+2Medaval+2
Best Supported: Huawei Watch D and Watch D2 - Fully Validated Watch-Type BP Monitors
Although not in the product carousel (since these are big-name “smartwatches” rather than generic monitors), the Huawei Watch D and Huawei Watch D2 deserve special mention:
The original Watch D was validated in a peer-reviewed study using the internationally accepted standard AAMI/ESH/ISO 81060-2 for BP monitors. The study found mean difference vs reference BP of −1.4 ± 6.47 mmHg (systolic) / −0.2 ± 5.85 mmHg (diastolic), which is within the acceptable range. Ovid+2PubMed+2
The Watch D2 has also been tested in rest and 24-hour ambulatory monitoring settings and met the ISO 81060-2:2018 accuracy criteria. PubMed+1
In a study comparing 24-hour blood pressure tracking with a conventional ambulatory BP monitor, the Watch D2 showed acceptable agreement for daytime and nighttime BP. PubMed+1
So, among wrist-worn “smartwatch”-like devices, the Watch D / D2 are the clearest examples that have independent, peer-reviewed validation with recognized medical-device standards.
Emerging: Aktiia / Hilo Band- First FDA-Cleared Cuffless Device (U.S, expected 2026)
In July 2025, the U.S. FDA granted 510(k) clearance to the Aktiia G0 / Hilo Band- a cuffless wrist-worn blood pressure monitor for over-the-counter use. PR Newswire+1
This marks the first time a cuffless, optical-sensor based BP monitor has gained such clearance in the U.S. PR Newswire+1
That said, as of late 2025 it appears Hilo’s U.S. release remains pending (expected 2026) so not yet widely available to U.S. buyers. xBloodPressure.com+1
Important Caveats and Limitations
FDA Warning (2025): As of September 2025, the FDA issued a public safety communication cautioning consumers about “unauthorized devices” that claim to measure BP including many wrist- or ring-based devices. The FDA warns that many devices on the market have not undergone formal review, and inaccurate BP readings can lead to serious health risks (misdiagnosis, delayed treatment, inappropriate medication changes, etc.). U.S. Food and Drug Administration
Validation standards are strict: To be considered “validated,” a BP monitor generally must meet protocols such as ISO 81060-2 (plus AAMI/ESH) with adequate population sampling, and show mean ± SD differences within accepted thresholds vs a reference sphygmomanometer. Ovid+2Nature+2
Wrist circumference, usage conditions matter: For devices like Watch D / D2, proper wrist circumference (per manufacturer spec), correct strap fit, and correct wrist-at-heart level positioning are important for accuracy. Ovid+1
Many commercial “BP smartwatches” remain unvalidated: Just because a watch claims to measure blood pressure often via optical/Pulse-Wave / PPG does not mean it’s been validated. According to the FDA, many such devices are “unauthorized devices.” U.S. Food and Drug Administration+1
What I’d Recommend to You & Your Readers
If your priority is a clinically credible wrist-worn blood pressure reading (or close to it), then:
Consider devices with documented validation especially Huawei Watch D / Watch D2 because they have peer-reviewed evidence showing acceptable accuracy.
If you use a wrist-cuff BP monitor (rather than a true “smartwatch”), make sure to follow positioning instructions strictly (wrist at heart level, strap snug but not too tight, remain still).
Monitor regulatory updates: the Hilo Band may become the first widely available cuffless and FDA-approved BP wearable in the U.S. (likely in 2026), which might broaden options.
Last but Not Least, I have started my own Personal Validation of my Buddi watch versus the Blood Pressure Machine at our Hillandale Office here at THD. Here's my first week Data:
MY Buddi Watch. Hillandale Regular Blood Pressure Machine
130/83/83 Right Arm: 147/71/81; Left Arm: 158/75/80
I plan on continuing this validation on a weekly basis for at least 3 Months.
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