Apple Watch uses optical sensors to track heart rate with strong accuracy during rest and workouts, though it’s not a medical ...

Researchers at Northwestern Medicine plan to give Apple Watches to thousands of people as part of a health study. The study is geared toward patients with atrial fibrillation, or AFib, the most common ...

Apple was forced to remove the blood oxygen monitoring two years ago amid a patent dispute, but a software update coming later today will revive the feature.