One of the most important metrics on a Fitbit tracker is the Estimated Oxygen Variation – and now that every tracker is fitted with an SpO2 sensor, everyone can take advantage. Blood oxygen can be ...

Put simply, SpO2 is a measure of blood oxygen saturation. The more oxygen you have in your blood, the higher your SpO2 levels are going to be. Seeing as our bodies need oxygen to survive, we can ...

is a senior reporter and author of the Optimizer newsletter. She has more than 13 years of experience reporting on wearables, health tech, and more. Before coming to The Verge, she worked for Gizmodo ...