Best 9 Smartwatches With An Oxygen Sensor (SPO2) In 2021

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

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.

Covid_19 has already affected more than half a million people around the world and it is spreading rapidly. So, far it has spread to more than 199 countries around the world and many countries have announced medical emergencies and Lockdowns to stop the spread of this novel coronavirus. The good news is that these steps have helped the governments to flatten the curve to some extent but still, WHO, CDC, and other Health agencies recommend taking extreme caution to avoid the infection.

 Pulse Ox Sensor on the popular Garmin Vivosmart 4

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 the 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

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

Best 9 Smartwatches And Fitness Trackers With An Oxygen Sensor/Monitor(SPO2)

Product ImageProduct NameOur Rating
Garmin Fenix 6X9.8
Fitbit Ionic9.7
Garmin Vivosmart 49.8
Garmin Fenix 5X Plus9.8
Garmin Vivoactive 49.7
Fitbit Versa Lite Edition9.8
GARMIN Forerunner 245 9.7
GARMIN Forerunner 9459.8
Fitbit Versa 29.7

What is Pulse Oximetry?

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

When it comes to finding the oxygen saturation, there are two types of methods which 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.

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

Now, you must be wondering how 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 the 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.

Why we need it and Who Uses It?

Pulse Oximeters (Oxygen Sensors) are used by the doctors to determine the oxygen saturation level in the patient’s blood. Oxygen is very important for our body, you can consider it as the 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 the Pulse Oximetry to determine if the person has a lung issue or not.

Apart from lung disease, the 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, the 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? Can I Count on them with my life?

Blood Oxygen measurement on my Cheap LetsFit Smartwatch which showed similar results as my other expensive Smartwatches

Although Smartwatches and wearable devices will play a huge roll 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 are measuring 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 VO2 Max measurement which measures your blood oxygen in effort, the SPO2 measurement must be taken while perfectly still and while resting. Any movement or effort before or during the test will effect 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 check.

Measuring blood Oxygen: Finger vs wrist

Zacurate Pro Series 500DL Fingertip Pulse Oximeter

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 and 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 are 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 than 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).

A good solution might be to buy an additional 20-30$ accurate finger pulse Oximeter on Amazon and compare it with your watch.

If they are matching most of the time then you will know that your watch works fine for you and you now can have a good sleep and SPO2 tracking.

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 the “Sleep Apnea” which is a sleep disorder and 8 out of 10 people who suffer from this problem don’t know about it.

blood saturation Garmin

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 6, 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 the potential sign of an issue. However, it is not an actual SPO2 Estimate.

According to Dr. Conor Henenghan, the 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 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?

Yes, the new Apple 6 does come with a pulse Oximeter.

Like I have mentioned above, The Apple Watch 6 is able to perform a spot on checks which will require you to stay very still for 15 seconds and overnight measurements.

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.

9 Best Smartwatches & Wearables with an Oxygen Sensor

If you have read down to this then you already know much about the Oxygen Sensors. In this section, we will share the 10 Best Smartwatches & Gadgets with an Oxygen Sensor.

1. Garmin Fenix 6X

Garmin Fenix 6X is an advanced Smartwatch that comes with the Oxygen Sensor. It is a premium smartwatch and it comes with tons of great features. The battery life is also impressive and it can last for 60 hours with GPS. However, it is pretty expensive and you can get it for $899.

2. Fitbit Ionic

Fitbit Ionic is another very capable smartwatch that comes with the SPO2 Sensor. Fitbit has recently rolled out an update that allows the Fitbit Ionic to provide an estimated Oxygen variation graph. The watch is capable of monitoring your sleep and also keep track of any disruption in the sleep. You can read the complete review of Fitbit Ionic on our website.

3. Garmin Vivosmart 4

Garmin Vivosmart 4 is a fitness band that comes with the SPO2 sensor which can help you know your blood oxygen level. Its waterproof design allows you to use it in the office, gym, pool, or anywhere else you want to use. The variety of colors makes it easier to pick the color of your choice. If you are looking for an accurate fitness band then Garmin Vivosmart 4 is a great option.

4. Garmin Fenix 5X Plus

Garmin Fenix 5X Plus is a premium smartwatch that also comes with the “Pulse Ox” sensor which not only accurately analyzes the sleep quality but also measures the oxygen saturation. It is a premium watch so it comes with the beautiful design and tons of great features. It is another very solid option for you.

5. Garmin Vivoactive 4

Garmin Vivoactive 4 is a mid-range smartwatch that comes with the “Pulse Ox” sensor to measure oxygen saturation. It also comes with the 5 ATM Water resistance, Garmin Pay, Respiratory tracking, and other advanced features. If you are looking for a solid watch in the mid-range segment then Garmin Vivoactive 4 is a great option.

6. Fitbit Versa Lite Edition

Fitbit Versa Lite Edition is a versatile smartwatch that comes with tons of great features. It also comes with an oxygen sensor that accurately measures the blood oxygen level. It is also available in multiple colors which makes it easier for you to pick the color of your choice. It is also very affordable considering the features you get.

7. GARMIN Forerunner 245

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.

8. GARMIN Forerunner 945

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.

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 GALILIEO 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.

9. Fitbit Versa 2

Fitbit’s new smartwatch supports Alexa, Amazon’s Virtual Assistant and features a range of features that are expected to be quite attractive to sports fans: a 24-hour pulse meter monitoring, sleep monitoring, and water resistance up to 50 feet deep, enabling monitoring of the user’s swimming abilities.

In addition, the Fitbit Versa 2 features over 15 different fitness modes with automatic detection and tracking (running, swimming, cycling and more), the ability to monitor menstrual periods for women, and lets you create personalized reminders for exercise.

The device includes a pedometer and distance meter, the possibility to monitor the user’s climbed floors during the day, and a 3-axis accelerometer.

It also incorporates Blood Oxygen Meter (SpO2), a built-in microphone to make calls, Bluetooth and WiFi support, altimeter and more.

The Fitbit Versa 2 battery life will last 5 days in one charge, at least according to the American manufacturer. The watch supports both iOS and Android users and comes with a dedicated silicone strap of various sizes.

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 the substitute for the professional medical equipment. If you feel that you are not feeling well then make sure to contact the health helpline and get the medical help. If you have any questions, please let us know in the comment section below. Also, visit our website for more useful guides.