Withings ScanWatch 2 Review: A Health-Focused Hybrid Smartwatch With Long Battery Life

The ScanWatch 2 looks like a regular watch at first, with its classic round dial and tiny OLED display. But underneath, it quietly tracks things like heart rate, ECG, blood oxygen, temperature, sleep and activity.

What I like about this idea is that the watch does not constantly demand your attention. It focuses more on keeping an eye on your health than turning your wrist into another smartphone.

Of course, that comes with a few trade-offs. The small display limits what you can do on the watch, its smart features are nowhere near an Apple Watch and some deeper health insights require Withings+.

So, is that trade-off worth it? Let’s take a closer look at the Withings ScanWatch 2, its health features, accuracy, battery life and the things you should know before buying it.

What Is the Withings ScanWatch 2?

When we refer to smartwatches nowadays, it is inevitable that we imagine small screen-lit gadgets. But Withings ScanWatch 2 is an exception. First of all, the Withings ScanWatch 2 is a health-oriented gadget presented under the disguise of an old analog watch. Indeed, the very first time you look at the device, you see classic hands moving across the watch face. But under such classic exterior hides a sophisticated set of sensors.

In contrast to normal smartwatches, which bombard you with third party applications, bright light and complicated menus, this watch serves as a purely health monitoring device. This watch is targeted at those individuals who wish to have an extremely close look at their physical well-being in terms of cardiac health, body temperature changes and sleep patterns, but they are fed up with the daily battery charging rituals of ordinary wearables.

While using this Withings ScanWatch 2 watch, I came across the fact that it is actually an ambient health device. It does not require any effort from your side to make it function. Rather, it just stays in the background and collects important health information.

Specifications

Specifications	Withings ScanWatch 2
Available Sizes	38 mm and 42 mm
Weight (Without Strap)	38mm: 34.6 g / 42mm: 52.6 g
Build Materials	Stainless steel case, stainless steel crown
Display Glass	Scratch-resistant Sapphire glass
Digital Display	0.63-inch Grayscale OLED (14,504 px, 282 PPI)
Battery Life	Up to 30 days per charge
Charging Details	2 hours to full charge via USB-C docking station
Water Resistance	5 ATM (water-resistant up to 50 meters)
Core Health Sensors	TempTech24/7 (temperature), Multi-wavelength PPG (heart rate), ECG, SpO2 (blood oxygen)
Motion & Environment	Accelerometer, Barometric altimeter, Ambient light sensor
GPS Tracking	Connected GPS (relies on smartphone connection)
Connectivity	Bluetooth Low Energy
Software Compatibility	iOS and Android via HealthSense OS
Price	$369.95 USD

Withings ScanWatch 2 Design: A Smartwatch That Looks Like a Traditional Watch

One of the biggest reasons I wanted to do this Withings ScanWatch 2 review was to talk about its design. The moment I strapped it onto my wrist, I felt an immediate sense of style. Most modern health trackers look like small computers, but the ScanWatch 2 looks like a genuine, high-end traditional watch. As a guy with average-sized wrists, I opted for the 42mm version, but it is also available in a sleek 38mm size for those who prefer a smaller fit. Both models feature standard watch lugs, 20mm for the larger model and 18mm for the smaller one. Because of this smart design choice, you can easily swap out the strap for any standard watch band to match your outfit. I wore the original setup to a formal dinner and it fit perfectly with my suit, yet it felt right at home when I wore it to the gym, too.

The overall build quality is simply exceptional. It is encased in durable stainless steel and features a stunning, scratch-resistant sapphire glass crystal over the dial, which gives me tremendous peace of mind. I am notoriously clumsy and despite accidentally bumping my wrist into door frames a few times, the glass remains flawless. Tucked inside that beautiful analogue face is a tiny 0.63-inch OLED grayscale display. From a technical standpoint, this little screen packs a surprising punch with 282 pixels per inch (PPI), meaning the high-contrast text is incredibly crisp and easy to read even in bright lighting. When it is turned off, the screen becomes completely invisible, leaving just a clean, elegant watch face. Furthermore, navigating your data is a highly tactile experience. Instead of smudging a touchscreen with your fingers, you simply twist the stainless steel rotating crown on the side to smoothly scroll through your health metrics.

Comfort is another huge factor for me because a device meant to track your sleep must be easy to wear all night. Since this watch is designed to be worn 24/7, I can confidently say that it feels featherlight on the arm. To be specific, the 42mm model weighs just 52.6 grams without the strap, while the 38mm is an even lighter 34.6 grams, so it never feels bulky. The standard fluoroelastomer band it comes with is soft, durable and flexible. It never causes any skin irritation, even when I sweat during intense workouts or toss and turn in bed. On top of that, the watch boasts a 5 ATM water resistance rating, meaning it can survive depths of up to 50 meters. Because of this, I never even have to take it off before jumping into the shower or doing a few laps in the pool. Honestly, wearing this timepiece day and night for this Withings ScanWatch 2 review has been an absolute breeze.

What Health Features Does the Withings ScanWatch 2 Offer?

ECG (Electrocardiogram)

Probably one of the most interesting aspects about the watch is the ECG feature that comes at medical level. By just placing your two fingers on the metal bezel for about 30 seconds, you are closing an electric circuit through your arms and chest and this will enable the watch to work like a single-lead electrocardiogram. This works by accurately measuring electrical signals that make your heart muscles contract. This helps in identifying the heart’s electrical waves timing to determine AFib, which is an irregular heart rhythm. In the testing, using the ECG feature has been quite effective and quick. The watch gives an immediate alert of whether your rhythm is normal and provides a clinical report that you can export as a PDF file.

Heart Rate Monitoring

The ScanWatch 2 features a new 16-channel multi-wavelength PPG (photoplethysmography) sensor. From a technical standpoint, this means the watch shines tiny LED lights into your skin and measures how much of that light is absorbed by the blood pulsing through your wrist. Because blood absorbs different wavelengths of light differently, the watch accurately calculates your exact heart rate and your Heart Rate Variability (HRV), the microscopic time differences between individual heartbeats that indicate nervous system recovery. I loved how it quietly monitored my baseline heart rate continuously throughout the day and night, alerting me only if it detected unusual spikes or drops. During workouts, it seamlessly tracked my heart rate zones, helping me understand exactly when I was burning fat or pushing my cardiovascular limits.

Blood Oxygen Tracking (SpO2)

Being able to monitor your SpO2 level may be an important parameter of your general respiratory system condition. In order to do this, the watch uses red and infrared light sensors that can shine through your wrist tissue and determine the color of your blood. If your blood is bright red, then it is saturated with lots of oxygen, but dark blood has less oxygen. Using optical sensors, your watch determines exactly what percentage of oxygenated hemoglobin is present in your blood. You can track your SpO2 level manually, in 30 seconds and also see your average levels during the night. This was especially comforting for me because it is done automatically while you are sleeping.

Sleep Tracking

Due to its high comfort and energy efficient battery life, using the device while sleeping is not an issue. Every morning, I got my “Sleep Score” calculated by the Withings app that considers my duration of sleep, quality, consistency and interruptions. In fact, the device uses the heart rate information along with its highly sensitive accelerometer to provide you with a sleep architecture chart, which breaks down your sleep cycle into REM, light and deep sleep phases. The feature that I like the most is Smart Wake-Up alarm. By tracking the real-time sleep phases, it gently vibrates your wrist when you are in the lightest phase of your sleep cycle.

Temperature Trends

Among the new features of the ScanWatch 2 is the TempTech24/7 feature. As opposed to simply measuring an arbitrary temperature point, it uses a small heat flux sensor alongside environmental temperature algorithms to distinguish between the exact changes in temperature that take place within your body. Through constant monitoring of this core body temperature round the clock, it takes into account the temperature in the surrounding environment and comes up with incredibly precise personal information. It will help measure physical recovery after a rigorous exercise session, as well as an early warning for fever and illness. Within a couple of weeks, I really enjoyed seeing how the app mapped out my miniscule temperature fluctuations.

Breathing Disturbances Detection

As you sleep, the watch is constantly searching for any breathing problems using an intricate algorithm where your SpO2 reading is correlated to your breathing rate and heart rate. If there is a sudden drop in your oxygen levels accompanied by an increase in heart rate, which is a physical reponse that implies sleep apnea or heavy snoring, this desaturation incident is recorded. It turns your bodily response to autonomic nervous system stimuli into an amazing device for monitoring your health.

Cycle Tracking

An additional noteworthy feature in the ScanWatch 2 is the detailed cycle tracking feature. Instead of simply entering data from a calendar, the watch uses the newly introduced TempTech24/7 technology that allows it to monitor your temperature during the night. Through the use of temperature changes, it will be able to retrospectively determine ovulation and period phase.

In addition to recording temperature information, this device gives you an option to enter information about your cycle symptoms, flow, menstruation days and moods either from its small screen or by means of the Withings app. Due to the high dependence of this system on constant body temperature changes, rather than simply on calendar calculations, this method proves to be highly efficient during transitional periods such as perimenopause and menopause.

What Activity Tracking Does the Withings ScanWatch 2 Offer?

Automatic Workout Detection and 3D Motion Sensors

The watch is equipped with the capability of automatically identifying activities such as walking, running, swimming and cycling through the use of a High Dynamic Range 3-axis accelerometer, which comes hand in hand with a sensitive internal altimeter. Together, the 2-sensors monitor your physical movements in a 3-dimensional space. The accelerometer identifies the gravitational forces and acceleration acting on the X, Y and Z axis to accurately identify your forward movement and sideways movement. The altimeter, on the other hand, identifies even the slightest atmospheric pressure changes that would indicate an ascent up a flight of stairs or climbing a difficult hill. Since this sensitive device is enhanced by sophisticated machine learning algorithms that have the capability of distinguishing the physics of a run and a swim, I did not need to manually launch the activity in order to walk at a brisk pace the watch just picked up my arm cadence and took care of the rest.

Active Calorie and Energy Expenditure Calculation

After recognizing your activity type, the watch does not simply rely on the number of steps taken to approximate the physical effort you have put forth. The watch makes use of the live heart rate measurements combined with the personalized information about your age, height, weight and biological sex to give an accurate measurement of the calories burned. In terms of technology, the software manages to distinguish between the Basal Metabolic Rate or the number of calories burned by the body just for survival and the calories burned actively. With the help of the live data taken from the optical PPG sensor during the workout session, the watch measures the heart load that is happening right now. The watch knows exactly how hard your heart works at any particular moment to convert the physical effort into the number of calories burned.

Cardio Fitness Score and VO2 Max Estimation

In addition to monitoring your energy expenditure throughout the day, the watch also analyzes your cardiovascular fitness level based on your Cardio Fitness Score. This score can be interpreted as an intelligent estimate of the maximum oxygen consumption level, your VO2 max. This parameter indicates your maximum oxygen consumption rate, i.e., the volume of oxygen your body can use during high-intensity exercises on the cellular level. Typically, in order to calculate the true VO2 max, one needs to run on a treadmill in a clinical sports laboratory with a special oxygen mask attached to their face. The ScanWatch 2, on the other hand, uses the correlation between your running speed (which can be measured using the GPS on your phone and the accelerometer inside the watch) and your heart muscles’ effort to maintain this particular speed in order to estimate your cardio endurance level.

How Accurate Is Withings ScanWatch 2?

When you read any Withings ScanWatch 2 review or buy a health-focused wearable, accuracy is the most critical factor. In my time testing the watch, I paid close attention to how its metrics compared to reality.

First, it is crucial to differentiate between wellness monitoring and clinical metrics. As I noted earlier, the ECG and SpO2 metrics in the ScanWatch 2 are clinically validated. In other words, they went through extensive independent tests to be in line with the requirements set by health authorities. To test this, I sometimes compared the results from a regular chest strap device that gives very accurate readings along with those of the ScanWatch 2. Every time, the readings were absolutely identical, which demonstrates the amazing precision of the new 16-channel sensors.

The step counting feature also worked brilliantly. Most standard smartwatches register fake steps when the user just moves his arms, but not the ScanWatch 2 it is far too intelligent for that. It totally neglected all those fake steps whenever I was just sitting at my table typing on my keyboard or whenever I was out driving around town on my errands during the weekends. It was able to record only those movements that were intentional on my part.

Moreover, the sleep tracker was able to accurately determine when exactly I went to sleep and when during the night I woke up momentarily to have some water. Nevertheless, it should always be kept in mind that there are certain physical elements that may influence the accuracy of the optical sensor. Such elements include putting the watch loosely, having dark tattoos on the wrist and being very hairy around the wrist. But if I put the watch tight enough right above my wrist bone, then the accuracy was just amazing all day long.

Battery Life

If there is one absolute reason to buy this watch, it is the phenomenal battery life. Modern digital smartwatches have conditioned us to accept the annoying daily chore of plugging our watch into the wall every single night. The Withings ScanWatch 2 completely destroys that expectation.

Withings officially claims up to 30 days of battery life on a single charge. During my usage, with continuous heart rate monitoring, active TempTech24/7 temperature tracking, regular daily workouts and nightly sleep tracking fully enabled, I easily managed to get about three and a half weeks before needing a top-up. The sheer freedom of going on a multi-week trip without even packing a proprietary watch charger is liberating. The hybrid design, relying on physical analog hands for the time and keeping the OLED screen off most of the day, is the brilliant secret behind this incredible endurance. When the battery finally does die, charging it from zero to full takes a mere two hours.

Smart Features: Where It Falls Behind

Because this watch is so heavily focused on medical health sensors and month-long battery life, it intentionally sacrifices traditional smart features.

The most obvious limitation is the tiny 0.63-inch display. While it can easily scroll text to show you incoming phone calls, WhatsApp messages or calendar alerts, reading a long text message on this tiny grayscale screen is a frustrating experience. It is great for a quick glance to see who is calling, but you cannot reply to messages, use voice assistants or view photos.

Furthermore, there is no built-in GPS. If you want to accurately track the exact route and distance of your outdoor run, you must carry your phone with you so the watch can piggyback off your phone’s GPS signal (known as connected GPS). There are also no third-party apps, no Spotify, no Uber, no Google Maps. If you want a mini-smartphone on your wrist to play games and browse the web, this watch will severely disappoint you.

Who Should Buy Withings ScanWatch 2?

You should get it if:

• You are seeking clinical-level health monitoring (ECG and TempTech24/7), but you don’t want all the distracting technology of a smartwatch.
• You love the beauty and elegance of an old-school, analog watch.
• You are completely sick and tired of having to charge your watch daily and you would like to have a battery life of about a month.
• You are looking for superior non-invasive sleep monitoring and a watch that you can comfortably wear to bed every single night.

Who Should Avoid Withings ScanWatch 2?

You should definitely skip it if:

• You are an avid runner or cyclist and you need built-in GPS in order to leave your phone at home while exercising.
• You enjoy using other applications, making phone calls using only your watch and making payments using NFC.
• You are looking for a big and bright color touch screen to see pictures and graphs of your exercises when you are running.
• You have been using either Apple Watch or Garmin watches for quite some time and you have been using their special fitness rings or badges.

Wrap Up

The Withings ScanWatch 2 is not trying to be the smartest watch on your wrist and that is actually what makes it interesting. It keeps the classic watch look, adds useful health tracking and can go for weeks without constantly asking for a charger.

It does have its limits, especially if you want a big screen, lots of apps or advanced sports features. But if you want a watch that quietly keeps track of your health without becoming another distraction, the ScanWatch 2 gets the idea right.

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