Blood Oxygen Monitoring

Blood oxygen monitoring, or “SPO2 tracking,” is a feature that’s arguably been long overdue to come to the Apple Watch — Fitbit actually beat Apple to the punch here — but it looks like it could finally arrive this fall with watchOS 7.

While the Apple Watch currently offers VO2 max measurements — the maximum rate of oxygen consumed during exercise — it can only do this by measuring the user’s heart rate, since a face mask is required to get truly accurate measurements. However, this is also a measurement that applies primarily to workouts. By contrast, SPO2, is intended to monitor the amount of oxygen in the blood on a regular basis, which could help to detect certain medical conditions as well as helping athletes pace themselves during strenuous workouts.

There’s some debate about whether new hardware would be required to properly support SPO2 monitoring; according to iFixit, the necessary hardware was there in 2015, and certainly the fact that Fitbit was able to add it to older models via a software update suggests that Apple should be able to do the same. As with some of Apple’s other health features, the delay likely comes down to making sure that Apple can get these readings with proper accuracy as well as getting the necessary regulatory approvals.