Blood oxygen level (SpO2)

Polar SpO2 estimates the amount of oxygen you have circulating in your blood using pulse oximetry technology.

What is a normal blood oxygen?

Blood oxygen, also known as oxygen saturation or SpO2, refers to the amount of oxygen carried by red blood cells in the bloodstream. Understanding your blood oxygen levels is a key indicator of wellness: changes to your baseline measurements can indicate shifts in your health and wellbeing.

For fitness purposes, blood oxygen readings can help you assess your body’s response to exercise over time. When hiking or training at altitude, oxygen saturation can also serve as a useful sign of your acclimatization to the environment.

What is a normal blood oxygen level?

Typically, most healthy people maintain a blood oxygen level within the range of 95 to 100%. Some people, however, live a a normal life with levels below 95%.

During sleep, slightly lower values are considered normal. Your blood oxygen levels may also be lower if you live at high altitude. Your healthcare provider will tell you what levels are acceptable for you.

Blood oxygen level chart

SpO2 values usually vary between 90 and 100%.

- Normal: 95-100%
- Below normal: 90-94%. Your blood oxygen level is lower than normal. Environmental factors such as altitude or physical conditions like asthma can cause lower SpO2 levels.
- Low: Less than 90%. If your blood oxygen level is low, you may experience more severe symptoms like shortness of breath and elevated heart rate. In this case, you should contact your doctor or healthcare professional.

Blood oxygen saturation

Check your blood oxygen level with Polar SpO2

Powered by Elixir™ biosensing technologies, Polar SpO2 uses pulse oximetry technology to estimate the amount of oxygen you have circulating in your blood. It emits two different wavelengths of light, red and infrared, through the skin and into the underlying blood vessels. Inside the blood vessels, the light interacts with the oxygenated and deoxygenated hemoglobin in the red blood cells. The amounts of reflected and backscattered light are used to calculate how much oxygen your blood is carrying.

All blood oxygen measurements are saved to Polar Flow along with altitude information. Use this information to track and analyze your body’s response to exercise over a period of time.

Important: The SpO2 measurement feature is not intended for any medical use, diagnosis, or treatment as such (including self-diagnosis or consultation with a doctor) and the data should not be used for any medical purpose.

SpO2 and training at altitude

At higher altitudes, the air contains fewer oxygen molecules, making it challenging for your body to transfer oxygen into your blood, resulting in increased fatigue and lower SpO2 levels. Reduced oxygen levels force your body to work harder.

When training at different altitudes, understanding your blood oxygen saturation can help you assess your exertion level and avoid overtraining.

As your body adapts to a higher altitude, you'll experience increasing oxygen saturation levels.

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The science behind the SpO2 sensor

Polar SpO2 is based on pulse oximetry technology, a scientifically proven method for estimating blood oxygen saturation measurements. Its results are comparable to direct arterial blood oxygen saturation measurements.

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