The new Apple watch can also measure your blood oxygen

The new Apple Watch can be summed up in two words: blood oxygen.

The ability to measure your blood’s oxygen saturation — an overall indicator of wellness — is the most significant new feature in the Apple Watch Series 6, which was unveiled this week and becomes available Friday. (The watch is otherwise not that different from last year’s Apple Watch.) The feature is particularly timely with the coronavirus because some patients in critical condition with Covid-19 have had low blood oxygen levels.

But how useful is this feature for all of us, really?