Most health wearables announce themselves — a thick glowing rectangle, a rubberized band screaming "I am quantifying myself." The Withings ScanWatch 2 takes the opposite approach: it looks like a watch your grandfather might have worn, and it hides FDA-cleared ECG, continuous SpO2, and clinically validated sleep apnea detection inside that classic shell.
This is the hybrid philosophy. Withings bets that the best health device is the one you actually wear every day — to every meeting, every formal dinner — without feeling like you strapped a hospital to your wrist.
In 2026, with Apple Watch dominating smartwatches, WHOOP owning recovery, and Oura leading sleep, the ScanWatch 2 occupies a genuinely distinct niche: the only device combining FDA-cleared ECG, FDA-cleared sleep apnea detection, continuous SpO2, and a 30-day battery inside something that passes as a dress watch.
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Withings ScanWatch 2
The only medical-grade wearable that genuinely looks like a traditional timepiece. Perfect for health-conscious users who refuse to wear a tech gadget.
At a Glance
30
Day battery life
Longest of any ECG-capable wearable
FDA
Cleared ECG
Single-lead AFib detection in 30 seconds
FDA
Sleep apnea detection
SpO2-based respiratory disturbance screening
$349
One-time cost
No subscription required — ever
Hardware: A Watch First
The ScanWatch 2 comes in 38mm and 42mm cases, three finishes, built from 316L stainless steel with a domed sapphire crystal (9H hardness). Pick it up and it feels like a $400 watch, not a $400 health gadget.
A small monochrome PMOLED display at 12 o'clock shows steps, heart rate, SpO2, and truncated notifications. It deliberately avoids becoming a smartphone proxy. Analog hands tell time the traditional way — and draw almost zero power.
Why 30-Day Battery Is Possible
The analog movement consumes less than 1% of total battery over a month. Every photon an OLED emits costs milliamp-hours — which is why Apple Watch Ultra 2 manages 36 hours while this analog hybrid manages 30 days.
Under the sapphire caseback: multi-wavelength PPG (heart rate + SpO2), single-lead ECG via the bezel electrode, a 3-axis accelerometer, and a skin temperature sensor. Five ATM water resistance covers pool swimming, showers, and rain.
| Spec | Details |
|---|---|
| Case sizes | 38mm / 42mm |
| Material | 316L stainless steel, sapphire crystal |
| Display | 0.63" PMOLED (monochrome) |
| Battery | Up to 30 days |
| Sensors | PPG, ECG, SpO2, accelerometer, skin temp |
| Water resistance | 5 ATM (50m) |
| Straps | Standard 18mm / 20mm — any third-party fits |
| Weight | ~40g (42mm, without strap) |
| Subscription | None required |
Medical-Grade Features
Withings holds more FDA 510(k) clearances than any other hybrid watch maker. Here's what each one actually does.
ECG: AFib Detection
Place your fingertip on the stainless steel bezel for 30 seconds. The algorithm classifies: normal sinus rhythm, atrial fibrillation detected, or inconclusive. Sensitivity and specificity above 95% in clinical validation.
What the ECG Cannot Do
It detects one arrhythmia — atrial fibrillation. It cannot identify ventricular tachycardia, heart block, or ST-segment changes. A "normal" result means AFib wasn't detected in that window — it does not mean your heart is healthy. Seek medical attention for chest pain or palpitations regardless of what any consumer ECG shows.
AFib affects ~33.5 million people worldwide and increases stroke risk 5x. Up to 40% of episodes are asymptomatic. A 30-second ECG you can take anytime creates screening opportunities that didn't exist a decade ago.
Sleep Apnea Detection: The Standout
This is where ScanWatch 2 differentiates itself most clearly. It carries FDA clearance for detecting moderate-to-severe obstructive sleep apnea through overnight SpO2 — a capability shared only with Apple Watch Series 10 among consumer wearables.
The algorithm detects cyclical oxygen desaturation patterns (3-4% dips occurring dozens to hundreds of times per night) and provides an Oxygen Desaturation Index estimate. An estimated 80% of moderate-to-severe OSA cases are undiagnosed — the barrier has always been access, not medical knowledge. This watch screens every night, automatically.
reviewing the Withings ScanWatch 2 for medical-grade health monitoring and sleep apnea detection
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Better SpO2 Readings
Wear snugly on top of your wrist, ensure the sensor sits flat against skin, and avoid sleeping with your watch arm tucked under a pillow. Consistent placement improves the algorithm's ability to distinguish real desaturation from sensor noise.
Health Tracking Beyond Medical Features
Sleep: Stages classified via accelerometer, HR, and SpO2. Sleep Score (0-100) weighs duration, depth, regularity, and interruptions. Accuracy is ~65-70% vs. PSG — behind Oura (78%) and WHOOP (73%), but adequate for trend monitoring.
Heart Rate and HRV: Continuous 24/7 monitoring. HRV measured overnight and presented as a raw trend — no readiness or recovery score. This appeals to users who want clean data to share with a cardiologist, not algorithmic training advice.
Activity: Steps, distance, elevation, and auto-detection for walking, running, swimming, cycling. No rep counting, no power zones, no route mapping. It knows you exercised. It doesn't coach you through it.
| Feature | Feature | ScanWatch 2 | Apple Watch Ultra 2 | WHOOP 5.0 |
|---|---|---|---|---|
| ECG | ECG | FDA cleared | FDA cleared | MG only (Life tier) |
| Sleep apnea detection | Sleep apnea detection | FDA cleared | FDA cleared | Not available |
| Sleep accuracy | Sleep accuracy | ~65-70% | ~70% | ~73% |
| Recovery score | Recovery score | No | Basic | Best in class |
| Battery | Battery | 30 days | 36 hours | 14+ days |
| GPS | GPS | Phone-connected | Dual-frequency | None |
| Subscription | Subscription | No | No | $199-399/yr |
| Price | Price | $349 | $799-899 | $199-399/yr |
No Subscription Trap
All core features — ECG, sleep apnea detection, SpO2, sleep tracking, activity — work fully at the $349 purchase price, permanently. The optional Health+ ($9.95/mo) adds deeper analytics but is genuinely optional. This stands in sharp contrast to WHOOP (mandatory) and Oura (needed for full insights).
Overall Assessment
The ScanWatch 2 earns its score through a combination no other single device replicates: FDA-cleared ECG, FDA-cleared sleep apnea detection, continuous SpO2, 30-day battery, and a design that belongs in a watch case. It loses points for below-average sleep staging, absent recovery analytics, and software that presents data without interpreting it.
✓Pros
- FDA-cleared ECG — clinical-quality rhythm check in 30 seconds, anytime
- FDA-cleared sleep apnea detection runs automatically every night
- 30-day battery eliminates charging anxiety and guarantees unbroken data
- Classic analog design appropriate in any context — boardroom, wedding, gym
- No mandatory subscription — $349 one-time, all features included
- Standard lugs accept any third-party watch strap
- Withings ecosystem unifies scale, BP monitor, thermometer, and watch data
✗Cons
- Sleep staging accuracy (65-70%) trails Oura (78%) and WHOOP (73%)
- No recovery score or training load management
- Tiny monochrome display — notifications are truncated and hard to read
- No built-in GPS
- Health Mate app shows data without coaching or interpretation
- ECG detects only atrial fibrillation — no other arrhythmias
Categorieresultaten
Best Medical Features (Hybrid Watch)
Withings ScanWatch 2 Winner
No other analog-style watch combines FDA-cleared ECG, sleep apnea detection, and continuous SpO2. More medical certifications in a dress-watch form factor than any competitor.
Runner-up: Withings ScanWatch Light
Best Battery Life (ECG-Capable)
Withings ScanWatch 2 Winner
30 days vs. 36 hours for the nearest ECG competitor (Apple Watch Ultra 2). An order-of-magnitude difference that fundamentally changes the user experience.
Runner-up: Garmin Venu 4
Most Stylish Health Wearable
Withings ScanWatch 2 Winner
Sapphire crystal, 316L steel, analog hands, standard lugs. The only medical-grade wearable that genuinely looks like a traditional timepiece.
Runner-up: Oura Ring 4
Frequently Asked Questions
No. Every core feature — ECG, sleep apnea detection, SpO2, sleep tracking, activity — works fully at the $349 purchase price. The optional Health+ ($9.95/month) adds deeper analytics but is not required.
It records single-lead (Lead I) vs. a clinical 12-lead ECG. Optimized for AFib detection with >95% sensitivity and specificity. Think of it as a focused screening tool — a 'normal' result means AFib wasn't detected, not that your heart is healthy.
No. It screens for moderate-to-severe OSA by detecting cyclical oxygen desaturation. A positive result should prompt a clinical polysomnography. The ScanWatch identifies who should get tested; the sleep lab provides the diagnosis.
Yes — full compatibility with iOS and Android via Withings Health Mate. This makes it the best medical-grade wearable option for Android users wanting ECG and sleep apnea detection.
They're surprisingly complementary. Oura provides superior sleep staging (78% vs 65-70%) and a Readiness Score. ScanWatch adds FDA-cleared ECG and sleep apnea detection — capabilities Oura doesn't offer. Wearing both isn't redundant.
