Galaxy Note 4: Blood Oxygen Saturation measurement

•  The blood oxygen saturation or SpO2 level shows the amount of oxygen in the blood. SpO₂ is an estimate of arterial oxygen saturation, which refers to the amount of oxygenated hemoglobin in the blood.

•  Reading your SpO₂ level works the same as reading your heart rate. 

•  There is a sensor to measure blood oxygen on Galaxy Note 4 at home or any where else, and you can see your blood oxygen level by doing just these simple settings on your Galaxy Note 4.

Steps to Measure Blood oxygen Level (Spo2)

1. Open the S Health app on your Note 4. (If it's not pre-installed on your phone, get it from Samsung Apps or Google Play Store)
2. If this is first time opening the S Health app, you need to do some initial setup.
3. Tap the More button on the top right corner of the screen, and then touch the Manage Items option
4. There you should see available health tracker options, including the Heart rate, SpO2, Stress, Blood glucose and Blood pressure. 
5. Make sure to toggle ON the SpO2 item and then go back to the S Health main view
6. Scroll down to the list of already added items, and then find the SpO2 card and tap the Measure button
7. Now place finger on the sensor, which is located at the back of your Galaxy Note 4, wait for the measurement to start and complete. 
8. Keep being still and quiet, until you get the result.
9. You can save your measured blood exygen (SpO2 level) and track it over the time.