It’s puzzling that the new Apple Watch doesn’t measure blood oxygen levels, yet it can track sleep apnea. Conversely, the Apple Watch Ultra S1 has an oxygen sensor but can’t track sleep apnea. This seems like a deliberate strategy by Apple to compel users to upgrade. By restricting a feature that necessitates blood oxygen for an accurate reading, they’ve eliminated the need for an oxygen sensor in the new watches, while the Ultra S1 has one but can’t perform sleep apnea tracking.