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How to measure blood oxygen level with Apple Watch?

How to measure blood oxygen level with Apple Watch?
How to measure blood oxygen level with Apple Watch?

We explained in this article how to measure the oxygen level in the blood (SpO2), which is one of the most important features expected with Apple Watch 6.

Apple Watch Series 6 came with a number of new features for tracking heart and respiratory health. Among these features, there is a sensor and Blood Oxygen application that allows to measure the oxygen level in the blood.

Decreasing oxygen levels in the blood is an important condition associated with COVID-19, as it has been associated with many diseases. Because the disease can be an obstacle to adequate oxygen intake. Doctors monitor SpO2 levels throughout the treatment process to determine the severity of cases such as COVID-19.

It can also occur due to low oxygen levels in the blood, ie hypoxemia, asthma, pneumonia or chronic heart diseases. Apple Watch aims to warn you beforehand against these possible risks of your body with the Blood Oxygen application offered in the Series 6 model.

How is the oxygen level (SpO2) measured in the blood?

The sensor in Apple Watch 6 is placed on the back of the smartwatch is for measuring blood oxygen levels. Using four sets of red, green, and infrared LED lights and four photodiodes that convert light into electric current, the sensor directs the lights into veins on your wrist and measures how much the light bounces back.

The sensor in Apple Watch 6 is placed on the back of the smartwatch is for measuring blood oxygen levels.
The sensor in Apple Watch 6 is placed on the back of the smartwatch is for measuring blood oxygen levels.

Medical details aside, the sensor is basically based on the different absorption of red and infrared light by blood with high or low oxygen content. With this technique, Apple Watch can determine the color of blood.

When the oxygen level in the blood is measured, the bright red result is considered a high level, while the dark red result means a low SpO2 level. The reason for this is that although oxygen is supplied to organs or muscles, the body cannot get enough oxygen from the same organs and muscles.

How to use Blood Oxygen app?

With Apple Watch 6, it is possible to measure SpO2 at any time. For this, simply open the application and follow the commands on the screen.

Measuring the oxygen level (SpO2) in the blood with Apple Watch takes about 15 seconds, and when complete, you can see the oxygen level as a percentage.

Your smartwatch will also take measurements periodically during the day, whether you are stationary, lying on the sofa or sleeping. Your blood oxygen readings will be synchronized with the Apple Health app.