Best 15 Smartwatches With An Oxygen Sensor (SPO2) In 2025

If you are looking for a smartwatch or fitness tracker with a built-in pulse monitor, you have come to the right place. Most smartwatches and fitness trackers have an optical heart rate monitor built-in. In this article, we will be looking at some of the best smartwatches and fitness trackers that have a pulse oxygen monitor(pulse oximeter) sensor built-in as well.

Blood Saturation became a parameter in discovering the Coronavirus in our bodies, the truth is that many smartwatch and fitness tracker manufacturers had incorporated Oximeters(Oxygen sensors/monitors) in their watches and fitness trackers long before this Virus showed up.

#Overview

How accurate are the Oxygen monitors in Smartwatches and fitness trackers? Can I trust them As A Medical Device? Are they FDA-approved? I will discuss these important topics in this post.

The Coronavirus (SARS-CoV-2) attacks the lungs and causes severe pneumonia which makes it difficult for the victim to breathe. According to WHO, a low Oxygen saturation level could be a sign that you possibly have the Covid_19 and you should seek medical assistance.

Apart from the Coronavirus, Oxygen Sensor can also help you find “sleep Apnea” which is a very serious sleep disorder and it can help you with your training progress as well.

Here is a Short video Explanation by Garmin

15 Best Smartwatches & Fitness Trackers with an Oxygen Sensor

In this comprehensive guide, I will share everything you need to know about Blood Oxygen levels. I will also share some of the best Smartwatches and wearables which can help you determine your Blood Oxygen level. Let’s get into it.

For outdoor enthusiasts who need extended battery life and detailed health tracking in extreme conditions, the COROS VERTIX 2S stands out with its impressive 40-day battery life and built-in oxygen sensor.

The watch’s durability shines with its sapphire screen and titanium bezel, while remaining lightweight at just 5.3 ounces. You’ll appreciate the tactile buttons and large digital dial when maneuvering with gloves during adventures.

Beyond its rugged design, you get extensive health metrics, global offline maps, and up to 118 hours of full GPS tracking—perfect for multi-day expeditions where reliable performance matters most.

How SpO2 Monitoring Works in Coros Vertix 2S

Designed for mountaineers and extreme athletes with specialized pulse oximeter hardware that functions reliably at high altitudes. Offers on-demand measurements plus optional continuous monitoring during sleep and activities. Battery-efficient implementation allows monitoring without significant power drain.

Best For: Adventure athletes and outdoor enthusiasts who need exceptional battery life, comprehensive mapping features, and durable construction for multi-day expeditions in challenging environments.

Pros:

• Exceptional battery performance with 40 days of regular use and 118 hours of full GPS tracking
• Premium durability with scratch-resistant sapphire screen and titanium bezel while maintaining a lightweight design
• Comprehensive navigation features with global offline maps and intuitive controls that work even with gloves

Cons:

• Some users report software bugs and syncing issues with certain devices
• Relatively low ranking (#157) in Running GPS Units category suggests potential limitations compared to competitors
• Mixed reviews regarding compatibility and integration with external fitness platforms and devices

Serious athletes and outdoor enthusiasts will appreciate the Garmin Fenix 8 AMOLED Sapphire’s extensive health monitoring capabilities paired with rugged durability. This premium 51mm GPS smartwatch features a scratch-resistant sapphire display and titanium bezel that can withstand harsh adventures.

You’ll get thorough performance metrics for training, recovery, and stamina building while enjoying the convenience of a built-in LED flashlight, speaker, and microphone. With 40-meter water resistance and TopoActive maps, it shifts effortlessly from mountain biking to swimming.

The impressive 16-day battery life guarantees you’re never left powerless during extended expeditions, making it worth the investment for dedicated fitness enthusiasts.

How SpO2 Monitoring Works in Garmin Fenix 8

Utilizes Pulse Ox technology with red and infrared LEDs to measure light absorption through blood vessels. Uniquely adjusts readings based on altitude for hikers and climbers. Offers spot-check measurements, all-day tracking, or sleep-only monitoring with adjustable frequency to balance accuracy with battery life.

Best For: Serious athletes, outdoor adventurers, and fitness enthusiasts who need comprehensive performance tracking, rugged durability, and extended battery life for multi-day expeditions.

Pros:

• Premium materials including scratch-resistant sapphire display and durable titanium bezel ensure longevity in harsh conditions
• Comprehensive tracking features with advanced metrics for training, recovery, and multiple sports activities
• Exceptional 16-day battery life eliminates charging concerns during extended outdoor adventures

Cons:

• Premium price point may be prohibitive for casual fitness enthusiasts
• Complex feature set may have a steeper learning curve for first-time Garmin users

The Ticwatch Pro 5 represents a significant leap forward for Android users seeking extensive health monitoring combined with exceptional battery life. Powered by Snapdragon W5+, it delivers impressive performance with 2GB RAM and 32GB storage.

You’ll appreciate the dual-layer display technology that extends battery life to 80 hours, with fast charging that takes you from 0-65% in just 30 minutes. Its blood oxygen monitoring works alongside extensive health features including heart rate tracking, sleep analysis, and stress monitoring.

The rotating crown enhances navigation while 100+ sport modes satisfy fitness enthusiasts. Remember, it’s Android-only, but if that’s your ecosystem, you’ve found your perfect wrist companion.

How SpO2 Monitoring Works in TicWatch Pro 5 Smartwatch

The TicWatch Pro 5 implements SpO2 monitoring through its advanced optical heart rate sensor array located on the underside of the watch. Here’s how the SpO2 monitoring system works in this device:

The sensor array contains red and infrared LEDs that shine light onto your wrist. As blood flows through your vessels, it absorbs different amounts of light depending on how saturated it is with oxygen. Oxygenated blood absorbs more infrared light and lets more red light pass through, while deoxygenated blood absorbs more red light and lets more infrared light pass through.

The watch’s photodiodes detect the reflected light, and the onboard processor uses proprietary algorithms to analyze the ratio of red to infrared light absorption, converting this into an SpO2 percentage value.

Best For: Android users who prioritize extended battery life, comprehensive health tracking, and a premium smartwatch experience with advanced fitness features.

Pros:

• Exceptional 80-hour battery life with fast charging capability (0-65% in 30 minutes)
• Comprehensive health monitoring including heart rate, blood oxygen, sleep tracking, and stress monitoring
• Powerful performance with Snapdragon W5+, 2GB RAM, and convenient navigation via rotating crown

Cons:

• Compatible with Android devices only, limiting its user base
• Relatively large and heavy design at 11.42 x 2.76 x 1.57 inches and 10.8 ounces
• Limited selection of free watch faces according to customer feedback

Fitness enthusiasts seeking extensive health tracking will find the Amazfit Balance Smart Watch an exceptional value proposition. Its thorough SpO2 monitoring integrates seamlessly with sleep analysis, tracking your heart rate, breathing patterns, and temperature to calculate daily readiness.

You’ll appreciate the impressive 14-day battery life (extendable to 25 days in saver mode), ensuring your tracking remains uninterrupted. The responsive Zepp OS delivers a lag-free experience across 150+ sport modes.

The watch’s body composition metrics measure your fitness journey beyond basic steps, while Alexa integration and Bluetooth calling add practical smartwatch functionality—all in a stylish design suitable for both workouts and daily wear.

How SpO2 Monitoring Works in Amazfit Balance

Uses BioTracker PPG optical sensor with multiple light wavelengths. Provides both on-demand and automatic overnight SpO2 monitoring. Analysis algorithms detect patterns of breathing disturbances and low oxygen events during sleep with consolidated reporting in the Zepp app.

Best For: Health-conscious individuals seeking a comprehensive fitness tracker with smartwatch capabilities that balances advanced health metrics, extended battery life, and everyday functionality at a competitive price point.

Pros:

• Exceptional battery life (up to 14 days regular use, 25 days in saver mode) minimizes charging interruptions
• Comprehensive health tracking including body composition, sleep analysis, and readiness metrics provides deeper insights than basic fitness trackers
• Versatile functionality with 150+ sport modes, Alexa integration, and Bluetooth calling combines fitness tracking with practical smartwatch features

Cons:

• Some users report inconsistencies with sleep tracking accuracy compared to specialized devices
• Limited app integration capabilities, particularly for Android users
• Learning curve for navigating all features and understanding the comprehensive health metrics

Samsung’s Galaxy Watch 7 40mm combines sophisticated oxygen monitoring with AI-driven insights, making it ideal for health-conscious consumers seeking extensive wellness tracking. This sleek timepiece features a premium stainless-steel frame with a customizable 40mm AMOLED display.

You’ll benefit from the watch’s Energy Score function, which uses AI to optimize your wellness by calculating daily energy expenditure and recovery. It tracks heart rate with improved accuracy, monitors sleep cycles, and even detects moderate to severe sleep apnea.

With up to 3+ days of battery life (without Always On Display), Bluetooth connectivity, and seamless integration with both Android and iOS devices, it balances functionality with convenience.

How SpO2 Monitoring Works in Samsung Galaxy Watch 7

The BioActive Sensor combines multiple health sensors including red and infrared LEDs for SpO2. Samsung’s system takes measurements by analyzing how the different wavelengths of light are absorbed as they pass through your fingertip or wrist. The watch offers continuous monitoring during sleep plus on-demand readings with trend analysis in Samsung Health.

Best For: Health-conscious individuals seeking comprehensive wellness tracking with AI-driven insights in a stylish, versatile smartwatch that integrates seamlessly with both Android and iOS devices.

Pros:

• Advanced health monitoring with improved heart rate accuracy, sleep cycle tracking, and sleep apnea detection
• Impressive battery life of 3+ days without Always On Display and convenient fast wireless charging
• Premium design with customizable 40mm AMOLED display and stainless-steel frame that looks better than advertised

Cons:

• Heart rate tracking, while improved, is not intended for medical use and may have limitations
• 40mm size may be too small for users with larger wrists who prefer a bigger display
• Battery life significantly reduces when using Always On Display, requiring more frequent charging

The Huawei Watch GT 5 Pro 46mm stands as a powerhouse for adventurers needing extended tracking without frequent charging. Its aerospace-grade titanium alloy construction with sharp-edged design offers both durability and style for your fitness-focused lifestyle.

You’ll appreciate the impressive battery performance—up to 14 days maximum or 9 days with typical use. The watch delivers thorough health monitoring with its advanced oxygen sensor, while the exclusive emotional wellbeing app uses TruSense data to assess your mental health in real-time.

For outdoor enthusiasts, you’ll benefit from wrist-based navigation with real-time, map-based routes for running, riding, and hiking adventures.

How SpO2 Monitoring Works in Huawei Watch GT 5 Pro

TruSeen 5.5 technology uses a combination of optical paths with AI algorithms to filter motion artifacts. Offers continuous SpO2 monitoring with minimal battery impact. Can alert users when levels fall below customizable thresholds, with detailed analysis of overnight variations.

Best For: Outdoor enthusiasts and fitness-focused individuals who prioritize long battery life, comprehensive health tracking, and navigation features in a premium smartwatch.

Pros:

• Exceptional battery life of up to 14 days allows for extended use without frequent charging
• Premium construction with aerospace-grade titanium alloy offers durability while maintaining a stylish appearance
• Advanced features including real-time navigation, comprehensive health tracking, and unique mental wellness monitoring

Cons:

• Sharp-edged design may not appeal to those seeking a more rounded, traditional watch aesthetic
• Premium materials likely come with a higher price point compared to standard smartwatches
• Fluoroelastomer strap may not be as comfortable or luxurious as leather or metal band options

Designed for serious athletes who demand thorough training metrics and extended battery life, the POLAR Vantage V3 stands out with its impressive oxygen monitoring capabilities.

The vibrant AMOLED touchscreen offers customizable dashboards while dual-frequency GPS with downloadable maps guarantees you’ll never lose your way on remote trails. With over 150 sport modes and up to 140 hours of training time, this powerhouse watch handles any adventure you throw at it.

Despite some users reporting inconsistent heart rate readings and occasional charging issues, the comfortable design and seamless app integration make the Vantage V3 a compelling choice for data-driven athletes monitoring their oxygen levels during intense workouts.

How SpO2 Monitoring Works in Polar Vantage V3

Advanced optical sensor optimized for athletes with special algorithms that account for circulation changes during intense exercise. Provides spot-check measurements plus automatic overnight tracking, with analysis focused on recovery optimization and altitude acclimatization for training purposes.

Best For: Serious athletes and endurance enthusiasts who need comprehensive training metrics, extended battery life, and navigation capabilities for remote outdoor activities.

Pros:

• Impressive battery life lasting up to 140 hours in training mode and 8 days with regular use
• Dual-frequency GPS with downloadable offline maps for reliable navigation on remote trails
• Versatile training companion with over 150 sport modes and customizable AMOLED touchscreen display

Cons:

• Some users report inconsistent heart rate readings during intense activities
• Charging issues with the original cord and variable recharge times (5-10 hours)
• Limited app functionality, particularly when editing maps and setting custom training goals

Boasting the impressive 45mm Actua display that’s twice as bright and 40% larger than previous models, Google’s Pixel Watch 3 stands out as a premium choice for Android users seeking extensive health tracking.

The sleek matte black aluminum case with obsidian band houses powerful fitness features including Fitbit’s advanced running metrics, custom workouts, and real-time guidance. You’ll appreciate the thorough health insights like readiness tracking and cardio load measurement to optimize your training.

With seamless Google Assistant integration and compatibility with Pixel phones (Android 10.0+), you’ll enjoy convenient notifications and app access. The 24-hour battery life requires daily charging, but users report efficient recharging with the included USB-C fast charging cable.

How SpO2 Monitoring Works in Google Pixel 3 Watch

Leverages Fitbit’s technology with an improved sensor array of red and infrared LEDs. Measures SpO2 primarily during sleep, presenting data as both percentage values and variation graphs. Algorithm designed to minimize false readings from movement or environmental factors.

Best For: Android users who prioritize sophisticated fitness tracking and want a smartwatch with an excellent display, seamless Google ecosystem integration, and advanced health monitoring capabilities.

Pros:

• Impressive 45mm Actua display that’s twice as bright and 40% larger than previous models delivers exceptional visibility and user experience
• Comprehensive fitness features including Fitbit integration, advanced running metrics, readiness tracking, and cardio load measurement
• Seamless integration with Google ecosystem including Google Assistant, Pixel phones, Pixel Buds, and Nest devices

Cons:

• 24-hour battery life requires daily charging, which may be inconvenient for some users
• Limited compatibility as it only works with Android 10.0+ devices, excluding iPhone users
• Higher price point compared to some competitor smartwatches with similar features

Garmin Venu 3S, with its built-in oxygen sensor, is ideal for health-conscious individuals who want to monitor their blood oxygen saturation levels throughout the day and night. This smartwatch lets you track your SpO2 levels, providing valuable insights into your respiratory health and overall well-being.

By measuring oxygen saturation, the Garmin Venu 3S helps you understand your fitness performance and identify potential health issues. You’ll get continuous data on your oxygen levels, whether you’re awake or asleep, offering a thorough view of your body’s needs.

With this information, you can make informed decisions about your health and fitness routines, ensuring you’re always at your best. The Garmin Venu 3S truly stands out as a must-have for those serious about their health.

How SpO2 Monitoring Works in Garmin Venu 3S

Utilizes Pulse Ox technology with red and infrared LEDs to measure light absorption through blood vessels. Uniquely adjusts readings based on altitude for hikers and climbers. Offers spot-check measurements, all-day tracking, or sleep-only monitoring with adjustable frequency to balance accuracy with battery life.

Best For: Health-conscious individuals who want to monitor their blood oxygen saturation levels throughout the day and night for a comprehensive view of their well-being.

Pros:

• Continuous SpO2 monitoring throughout the day and night.
• Provides valuable insights into respiratory health and overall well-being.
• Helps users make informed decisions about health and fitness routines.

Cons:

• May require frequent charging due to continuous monitoring.
• Advanced features might be overwhelming for casual users.
• Higher price point compared to basic fitness trackers.

The Withings ScanWatch 2, with its advanced oxygen sensor, is perfect for health-conscious individuals seeking reliable SpO2 monitoring throughout their daily activities. This smartwatch provides accurate blood oxygen level readings, giving you valuable insights into your overall health and fitness. Its focus on health tracking helps detect potential respiratory issues or changes in oxygen saturation, ensuring you stay informed about your wellbeing.

You can monitor your SpO2 levels during sleep, exercise, and everyday activities, offering a thorough view of your health. The oxygen sensor seamlessly complements the ScanWatch 2’s other health monitoring features, making it an invaluable tool for managing your wellness.

With the Withings ScanWatch 2, you’re equipped to take proactive steps towards better health.

How SpO2 Monitoring Works in Withings ScanWatch 2

Features medical-grade SpO2 monitoring (clinically validated) through a dedicated sensor cluster. Measurement is primarily on-demand through a 30-second test sequence. The watch guides proper positioning for accurate readings and can notify of significant overnight drops in oxygen levels.

Best For: Health-conscious individuals looking for reliable and comprehensive SpO2 monitoring throughout their daily activities.

Pros:

• Accurate blood oxygen level readings for insightful health tracking.
• Ability to monitor SpO2 levels during sleep, exercise, and daily activities.
• Seamlessly integrates with other health monitoring features for comprehensive wellness management.

Cons:

• May require regular charging due to continuous health monitoring.
• Advanced features might be overwhelming for casual users.
• Potentially higher price point compared to basic fitness trackers.

For those wanting to monitor their blood oxygen saturation levels throughout the day, the Fitbit Sense 2 offers a dependable and thorough solution. It’s equipped with an oxygen sensor that measures your blood oxygen saturation levels, giving you insights into your overall health and wellness. You can track changes in your blood oxygen levels throughout the day, helping you understand how your body is functioning and how you might need to adapt your lifestyle.

The Fitbit Sense 2’s oxygen sensor provides a detailed health monitoring experience by offering valuable data on your oxygen saturation levels. This feature helps you stay informed about your body’s needs and make more informed health decisions. It’s an essential tool for anyone serious about maintaining their health.

How SpO2 Monitoring Works in Fitbit Sense 2

Multi-path optical heart rate sensor includes red and infrared LEDs for SpO2 detection. Primarily measures during sleep automatically, displaying your “Estimated Oxygen Variation” with graphs showing fluctuations rather than specific percentages. Data integrates with Fitbit’s sleep scoring system to detect potential breathing disturbances.

Best For: Individuals who want to continuously monitor their blood oxygen saturation levels for better health and wellness insights.

Pros:

• Advanced oxygen sensor for accurate blood oxygen saturation measurement.
• Provides continuous tracking of oxygen levels throughout the day.
• Helps users make informed health decisions based on detailed oxygen saturation data.

Cons:

• May require regular calibration for accurate readings.
• Potentially higher cost compared to models without oxygen sensors.
• Battery life may be impacted by continuous monitoring features.

Fitness enthusiasts will appreciate the Polar Grit X Pro’s advanced oxygen sensor for tracking blood oxygen levels during intense workouts. This smartwatch comes with a SpO2 sensor that delivers real-time oxygen saturation readings, giving you valuable insights into how well your body is absorbing oxygen.

By monitoring your oxygen levels, you can optimize your performance and recovery during various activities. The Polar Grit X Pro’s oxygen sensor enhances your overall health and fitness tracking, providing you with data that can help improve your training regimen.

You’ll find this feature particularly useful for monitoring your body’s response to strenuous exercises, ensuring you perform at your best while maintaining peak health.

Best For: Fitness enthusiasts looking to optimize their performance and recovery by tracking blood oxygen levels during intense workouts.

Pros:

• Real-time oxygen saturation readings with the advanced SpO2 sensor.
• Enhanced health and fitness tracking capabilities.
• Valuable insights into the body’s oxygen absorption during activities.

Cons:

• May require frequent calibration for accurate readings.
• Potential for discomfort during continuous wear.
• Higher price point compared to basic fitness trackers.

The Fitbit Charge 6 is an excellent fitness tracker with an oxygen monitor. For the first time, the Fitbit Charge lineup includes an oxygen monitor, which makes it a great choice for serious athletes and fitness enthusiasts.

The Charge 6 offers all the standard features of the Charge 5, including heart rate monitoring, step counting, sleep tracking, and calorie burn estimation.

What’s more, Fitbit’s smartwatch app is excellent(my favorite one) and the Charge 6 includes a built-in GPS.

The predecessor to Charge 6 also has many convenient features to offer. Allow the built-in GPS to measure your covered distance and pace every time.

Integrated SpO2 keeps tracking your oxygen level in the blood. You can measure an average during nap time, workouts, and trends. Looking into the readings from the week should keep up the pace.

However, HR monitoring is more active with a 24/7 functionality. Also, you can check the burnt calorie and skin temp variations. Overall readings can help you set the perfect fitness management.

There are more than 20 goal-based workouts included for your fitness tracking. Meantime, the multi-day battery is ready to serve your needs for 7+ days. And all this at a very reasonable price.

How SpO2 Monitoring Works in Fitbit Charge 6

Multi-path optical heart rate sensor includes red and infrared LEDs for SpO2 detection. Primarily measures during sleep automatically, displaying your “Estimated Oxygen Variation” with graphs showing fluctuations rather than specific percentages. Data integrates with Fitbit’s sleep scoring system to detect potential breathing disturbances.

With so many advanced features, the Forerunner 245 running watch makes it ideal for runners of all levels. With blood oxygen measurement (Pulse OX) measurement, pulse, built-in GPS, VO2 Max, running dynamics analysis, and more, users can enjoy a close-to-wrist training program, analyze performance, get information on recovery times, and get better.

Similar to the more advanced models in the series, Forerunner comes in 2 versions of Forerunner 245 and Forerunner 245 Music to enjoy music while running without the need for a mobile phone, with up to 500 songs storage space and connectivity to popular music services, including Spotify and Deezer.

In addition, the watch also offers the option of sending an SOS distress signal for location sharing when in trouble with selected contacts. Forerunner 245 has long battery life, up to 7 days in smartwatch mode and up to 24 consecutive hours in GPS mode or 6 consecutive hours in GPS mode with music.

How SpO2 Monitoring Works in the Forerunner 245 running watch

Utilizes Pulse Ox technology with red and infrared LEDs to measure light absorption through blood vessels. Uniquely adjusts readings based on altitude for hikers and climbers. Offers spot-check measurements, all-day tracking, or sleep-only monitoring with adjustable frequency to balance accuracy with battery life.

The Elite Multi-Sports Watch offers a perfect fit for runners, riders, swimmers, or in short – triathletes.

The Forerunner 945 will guide the user in any sporting activity and help monitor particularly advanced physiological characteristics, maintain training load balance, analyze performance history, and more.

How SpO2 Monitoring Works in Forerunner 945

Utilizes Pulse Ox technology with red and infrared LEDs to measure light absorption through blood vessels. Uniquely adjusts readings based on altitude for hikers and climbers. Offers spot-check measurements, all-day tracking, or sleep-only monitoring with adjustable frequency to balance accuracy with battery life.

Alongside the familiar and beloved features of the GARMIN multisports watches, the Forerunner 945 is equipped with new and essential features that have so far been the exclusive possession of more expensive models, including a powerful battery, GPS reception from 3 satellites including GALILEO for fast and stable spotting, fast-dialing SOS emergency service for a predefined number during distress, measuring Pulse Ox blood oxygenation and, for the first time, direct listening to music with up to 1,000 songs storage and connecting to popular music services, including Spotify and Deezer.

How SpO2 Monitoring Works in Modern Smartwatches

Smartwatches measure blood oxygen saturation (SpO2) using pulse oximetry technology, where red and infrared LED lights are projected through the skin onto blood vessels in the wrist.

The sensors detect how much light is absorbed or reflected back, with oxygenated blood absorbing different wavelengths than deoxygenated blood. The smartwatch’s algorithm then calculates the SpO2 percentage based on this light absorption pattern.

Leading smartwatches implement this technology in two primary approaches: continuous monitoring (ideal for sleep analysis and detecting respiratory issues) and on-demand measurements (better for battery life).

Among the featured devices, the Samsung Galaxy Watch 7 offers continuous SpO2 monitoring during sleep and on-demand measurements while awake.

The Google Pixel Watch 3 primarily uses on-demand measurements to preserve battery life. Amazfit Balance provides both continuous nighttime monitoring and on-demand daytime readings. Garmin devices generally feature continuous SpO2 monitoring with dedicated pulse ox sleep tracking, while Fitbit offers primarily nighttime continuous monitoring.

The Apple Watch provides both on-demand measurements and background readings during sleep, and Xiaomi watches typically offer on-demand measurements with some models supporting limited continuous monitoring during sleep sessions.

What is Pulse Oximetry?

Pulse Oximetry is the technique to determine oxygen saturation (SO2). Pulse Oximeters are mainly used in clinics and Hospitals. Pulse Oximeter, as it sounds, is a combination of a pulse meter and an Oximeter.

When it comes to finding oxygen saturation, there are two types of methods that are mainly used.

• SPO2 – Peripheral Oxygen saturation (SPO2) – It is an indirect and non-invasive approach. In this method, we use the pulse Oximeter.
• SAO2 – Arterial Oxygen Saturation (SaO2) – It is a direct but invasive approach. In this method, the doctors use the blood test known as “Arterial blood gas study (ABG)” to know the oxygen saturation level in your blood.

Modern Smartwatches come with the SPO2 sensor which helps them determine the Oxygen saturation in your blood level.

Now, you must be wondering how the Pulse Oximeter works. According to the American Thoracic Society:

“A Pulse Oximeter comes either as a small unit with a built-in finger/toe clip or a small handheld device that has a probe that can attach or be applied to your finger, toe or earlobe… A beam of light from the device passes through the blood in your finger (earlobe or toe) to measure your oxygen”.

The smartwatches work the same way as the simple finger clip only that they send the beam of light from your wrist instead of your finger.

When it comes to Pulse Oximeters, they show blood saturation in the form of a percentage. However, it can also vary from vendor to vendor. For example, Fitbit shows the oxygen saturation level in the form of a graph which we’ll discuss later in the article.

Looking for a Smartwatch that can monitor blood pressure? check out my post on the Best 5 Android Smartwatches with ECG Monitoring that are FDA Approved.

Why Do We Need It and Who Uses It?

Pulse Oximeters (Oxygen Sensors) are used by doctors to determine the oxygen saturation level in the patient’s blood. Oxygen is very important for our body, you can consider it as a crucial gas and our body can’t function without it.

Our lungs play an important role as they allow us to inhale the oxygen which gets mixed into our blood and then passes on to our cells.

When a person gets any lung disease, the oxygen saturation levels get low and doctors use Pulse Oximetry to determine if the person has a lung issue or not.

Apart from lung disease, doctors also use this test for various medical conditions which can affect the blood oxygen levels such as asthma, pneumonia, lung cancer anemia, heart attack, and others.

The Optimal Blood Oxygen Level

In the medical world, the process of measuring oxygen saturation level using the pulse Oximeter is known as “O2 Sat” (SPO2). We will try to keep the terms as simple as possible and the following guidelines will help you determine your oxygen saturation level and whether you need to contact a doctor or not.

• If your reading is between 95 and 100% then it is completely normal.
• If your reading is below then 95%, it is considered low and you should get in touch with your doctor.

In the case of Coronavirus, Severe Pneumonia is the most significant symptom. According to the WHO interim Guidance document for Coronavirus, patients with severe pneumonia have oxygen saturation (SPO2) of less than 90% on room air.

How Accurate are The Finger Pulse Oximeters?

According to the American Thoracic Society

“The Oxygen level from a finger pulse Oximeter(the ones that are being used at medical facilities) is reasonably accurate. Most finger Oximeters give a reading 2% over or 2% under what your saturation would be if obtained by an arterial blood gas (ABG)”.

The same document also mentions that “The Oximeter reading may be less accurate if a person is wearing nail polish, artificial nails, has cold hands or poor circulation”.

These are the different factors that affect the accuracy of Finger Pulse Oximeters.

How Accurate are The Smartwatches Pulse Oximeter Sensors?

Smartwatches and wearable devices will play a huge role in the future of the medical industry, and we read about lots of cases in which Smartwatches helped to save lives.

When it comes to SPO2 Sensors in Smartwatches, meaning that they are reading the SPO2 from the wrist, their accuracy is not that great and it depends on many factors.

You see, Smartwatches measure your SPO2 from your wrist, therefore variants like skin tone, fat levels, blood vessels, proper wearing, and proper straps will affect the readings.

In addition, in opposite to the VO2 Max measurement which measures your blood oxygen in an effort, the SPO2 measurement must be taken while perfectly still and while resting. Any movement or effort before or during the test will affect it tremendously.

That being said, no, you cannot trust them with your life. If you have medical problems or you are not sure about your health, consult with a doctor. These gadgets are not a replacement for medical checks!

Measuring blood Oxygen: Finger vs wrist

These words by Fitbit’s director of research, Conor Heneghan will summon it up for you:

“It’s a pretty hard technical problem to measure SpO2 on the wrist, Unlike fingers, which have many blood vessels near the surface that offer a strong signal, the wrist is prone to obstructions and poor readings. You move a little bit, or even just you are a little bit colder than normal, you can get a very weak signal,” Heneghan said. “We’ve gone after long-term averaging, so that way, when we take overnight measurements, we can comfortably exclude the periods when we feel that signal is too noisy or weak to be reliable.”

This is the reason why the Fitbit, in opposition to the Apple Watch 6 that performs spot checks while you sleep, will only measure your SPO2 levels while sleeping and will give you an overnight review.

Are Pulse Oximeters on Finger and on Smartwatches FDA Approved?

While many of the finger pulse Oximeters brands are FDA approved(Medline for example), none of the Smartwatches are FDA approved.

So, If I cannot really Trust their Accuracy, Should I Buy A Smartwatch With An Oxygen Sensor?

Well, that depends on your expectations. If you are looking for a trustful Pulse Oximeter for purely medical reasons then you can buy a 50$ Finger Oximeter from Medline which is FDA approved.

If you want a Smartwatch for the tons of features and the fun that it brings and SPO2 readings that are quite accurate(especially as an overnight measurement device) then sure, go for it, Smartwatches are great.

In addition to that, many users are reporting accurate SPO2 readings from the watches(even the spot-on checks) and it could be that it will work fine for you(providing that you wear it tight enough).

Here is a related post that I have written that might interest you about the Best 5 Wearable Blood Sugar/Glucose Monitor Devices.

Can Garmin measure Blood Oxygen And How accurate is It?

Garmin is one of the most popular companies out there and the company has introduced its Oxygen Sensor “Pulse Ox” in their Smartwatches and fitness bands.

The main purpose of this sensor in Garmin watches is to detect “Sleep Apnea” which is a sleep disorder and 8 out of 10 people who suffer from this problem don’t know about it.

The Garmin Pulse Ox sensor monitors the blood oxygen level and then you can use the data to know if you have this problem or not.

Garmin’s watches, like the Apple Watch, allow you to perform a spot on check-in which you will require to stay still for 30 seconds. It also performs overnight tracking.

When it comes to accuracy, the official FAQ section does mention that:

“… [Accuracy] can be influenced by Altitude, activity, and an individual’s health”. The section also states that if your Pulse ox during sleep reading seems slow then it could be due to incorrect posture. The website recommends to main a position that is “conducive to good circulation and at or around heart level”.

Can Fitbit Measure Blood Oxygen and How Accurate Is It?

Some Smartwatches and fitness bands by Fitbit(mentioned in the list below) also come with the SPO2 sensor which is mainly focused on the Sleep Apnea problem. Instead of showing the percentage, Fitbit shows the “Estimated” Oxygen variation in the form of a graph.

The graph highlights the big variation in the graph that could be a potential sign of an issue. However, it is not an actual SPO2 Estimate.

According to Dr. Conor Henenghan, Fitbit’s Lead Sleep Research Scientist, “We are not claiming this [graph] can be used to correlate with sleep apnea status… This graph is another opportunity for us to provide more data to our users”.

He also said, “Seeing frequent big variations is a clue that you may be experiencing breathing during sleep – something you might want to talk to your doctor about”.

How accurate is Withings’ Pulse Oximeter?

Withings also has recently launched the “ScanWatch” which is also focused on Sleep Apnea. It comes with the SPO2 sensor which can monitor the blood oxygen level and provide alerts of any potential problems. It is currently waiting for clearance by the FDA.

Can the Apple Watch measure Blood Oxygen?

While older versions of The Apple Watch can measure blood oxygen levels, the 9th and the new 10th versions no longer have this capability. Please consider this before making a purchase.

Allow me to elaborate on this topic.

Basically, Yes, the Apple Watch Series 9,10 can measure blood oxygen levels using the built-in Blood Oxygen app. However, there are some important caveats:

• For Apple Watch units sold in the United States on or after January 18, 2024, the blood oxygen monitoring feature has been disabled due to a patent dispute with medical tech company Masimo. These units have part numbers ending in “LW/A”.
• Outside of the US, the Blood Oxygen app continues to function normally on the Apple Watch Series 9 and allows users to measure their blood oxygen saturation (SpO2) levels.
• The Blood Oxygen app provides on-demand measurements as well as periodic background readings when the user is inactive. It uses a bright red light on the watch’s sensor to estimate SpO2 levels.
• To take a measurement, users need to keep their arm still with the watch facing up for around 15 seconds. The results are then displayed on the watch.
• All blood oxygen data is synced to the Health app on the user’s iPhone for tracking over time.

So in summary, while the Apple Watch Series 9,10 is technically capable of blood oxygen monitoring, the feature has been disabled for new units sold in the US due to legal issues, but continues working as intended in other countries.

For previous Apple watch versions, you can find in the App Store a dedicated “Pulse Oximeter” app that uses the camera to detect pulse and Oxygen levels from your fingertip.

However, the app mentions that “The Pulse Oximeter app is not intended for Medical Use” and is “only designed for general fitness and wellness purposes.” This option is very inaccurate and I would not recommend using it.

Is there a Xiaomi watch with Oximeter?

Xiaomi offers tons of great smartwatches, but only very few of them come with a built-in Oximeter (SPO2 Sensor). The first Xiaomi watch that comes with Oximeter is the Xiaomi Mi Watch. The premium smartwatch by the company offers a full-fledged and functional SPO2 Sensor that you can use to keep track of your blood oxygen levels.

If you want something affordable from Xiaomi and still want the Oximeter, you can consider Mi band 6 and 7 which also come with a built-in SPO2 Sensor.

Frequently Asked Questions [ FAQs ]

What New Smartwatches Are Coming Out in 2024?

In 2024, you’ll see the Apple Watch Ultra 2, Apple Watch SE 2, Samsung Galaxy Watch 7 series, Google Pixel Watch 2, and OnePlus Watch 2. These new smartwatches promise advanced health metrics and improved performance.

What Smartwatch Do Cardiologists Recommend?

Cardiologists recommend the Apple Watch Series 9 and Samsung Galaxy Watch 6 Classic. Both offer accurate Health and ECG monitoring, helping you track your health and detect issues like respiratory problems and sleep apnea effectively.

What Is the Best Smartwatch for Health Monitoring?

For the best health monitoring, you should consider the Apple Watch Ultra 2. It offers advanced features like sleep tracking, ECG, and blood oxygen monitoring, making it a top choice for thorough health insights.

Question: Can A Smartwatch Actually Measure Oxygen Levels?

Answer: Almost all major smartwatches have a particular SpO2 sensor to measure blood oxygen. You can even take readings during intense workloads or workouts.

Question: How Accurate Is The Oxygen Sensor In Smartwatches?

Answer: The practical measurement accuracy is ±2% within 80% to 100% SpO2. However, the accuracy reduces to ±3% when the SpO2 remains within 50% – 80%.

Question: Can I Use A Smartwatch Instead Of An Oximeter For Oxygen Levels?

Answer: You should stick with an oximeter to use the reading for treatment purposes. Oximeter readings are more accurate compared to the sensory smartwatch.

Question: Why Do I Need To Measure The Oxygen Level?

Answer: Fitness-centered smartwatches offer various premium health metrics. And the suggested calculations require your approximate blood oxygen level.

Bottom Line

That’s all folks. These are some of the best Smartwatches with an oxygen sensor. You can use these watches to get an idea about your blood oxygen level. However, these watches can’t be a substitute for professional medical equipment. If you feel that you are not feeling well then make sure to contact the health helpline and get medical help.

If you have any questions, please let us know in the comment section below. Also, check out my post on the best Smartwatches with VO2 Max.