With Apple Watch Series 6, a new sensor was introduced, capable of measuring blood oxygen levels. If you are the owner of one Apple Watch compatible with this feature, in this tutorial you will see how to correctly measure the blood oxygen level with Apple Watch.
Before you see how to properly measure blood oxygen saturation (Blood Oxygen) with Apple Watch 7, we must know that this feature of Apple Watch 6 and Apple Watch 7, is not intended for medical purposes, but only for fitness si wellness. Let's find out the oxygen saturation in the blood during some physical exercises or while we relax.
I tested this feature in parallel with a medically approved pulse oximeter, and I noticed that most of the time, Apple Watch Series 7 gives the same results. Both for BPM (pulse) and for the blood oxygen level.
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What is oxygen saturation and what is the normal level
The level of oxygen in the blood is given by the amount of oxygen transported of red blood cells, from the lungs all over the body.
The optimal level of oxygen saturation in the blood is 95% - 100%, but we must also take into account the conditions under which the measurement is made. During sleep, in closed rooms that are not properly ventilated, the level can be slightly below 95%. This does not mean that you have a medical problem.
Another factor that may influence oxygen saturation of the blood is altitude. If you normally have a saturation of 98% - 100%, it is very possible that in the mountains, at high altitudes, this percentage will be lower. We all know that in the mountains, although the air is cleaner, it is even rarer, and the higher the altitude, the lower the oxygen concentration.
In fact, if we measure our oxygen saturation with Apple Watch when we are at high altitude, we are also informed that the measurement was made in high altitude conditions.
"Measurement taken in a high elevation environment."
Apple Watch 6 (or newer models), next to the measuring sensor blood oxygen, it also has sensors capable of measuring the altitude at which we are. Elevation.
How to correctly measure the level of oxygen in the blood with Apple Watch
To correctly measure the oxygen level in the blood with Apple Watch, you have to pay a little attention to the steps below.
1. First of all, make sure that both on iPhone and on Apple Watch you have the latest software versions. iOS and watchOS. Being an application developed by Apple and which is related to a feature of the device, it comes installed together with watchOS and is updated with it.
2. Make sure that this feature is available in your country. In some countries, due to the regulations in force, the oxygen saturation measurement application is not available.
3. Apple Watch must be visible the strap should not be tight but not too wide, here the wrist should be straight. As shown in the image below.
4. The hand to be relaxed, do not clench your fist and do not move it during the oxygen saturation measurement.
5. The best measurement is done keeping the arm relaxed on a table, with the screen facing us. Press "Start” in the Blood Oxygen application and wait 15 seconds. That's how long it takes for the measurement to be relevant.
Factors that can prevent the correct measurement of oxygen saturation in the blood
1. The strap should be too tight or too light on the wrist.
2. Temporary or permanent skin changes in the wrist area where you are holding Apple Watch. A tattoo, scar, or other skin change in that area may prevent the sensor light from scanning the blood vessels carefully, and the result may be erroneous.
3. Keeping your arms down next to your body or your fingers clenched into fists will result in incorrect measurements.
4. A very high heart rate will influence the results of measuring oxygen saturation. If you have a 150 BPM pulse at rest, the measurement result will not be relevant.
Measurement of oxygen saturation in the blood with Apple Watch 6 and Apple Watch 7 is done with the same sensors that were originally designed to measure heart rate. They have been redesigned to have the ability to measure oxygen saturation.
During the measurement you will notice on the back of the watch LEDs in red and green. In addition to these visible lights, the sensors also send infrared light to the skin, to make the measurements. The photodiodes measure the beam of light reflected back by the skin, and thus it is established through an algorithm, the level of oxygen saturation in the blood.
