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The first usable clinical device used for pulse oximetry was developed from this technology by Susumu Nakajima and was tested on patients beginning in 1975.
The difference range between absorption using an infrared light and a red light is used to gauge the SpO2 percentage.
Low blood oxygen level mean that the body will transport oxygen to the muscles at a slower pace, which will cause fatigue and make the workout less effective.
Since hemoglobin accounts for over 90% of oxygen in blood, SpO2 also measures the amount of oxygen in blood.
Hypoxemia is a sign of a problem related to breathing or circulation, and may result in various symptoms, such as shortness of breath.