Will the Apple Watch always track your heart rate in the background, or only when you explicitly instruct the Watch to track your heart rate? - Quora
![How the Apple Watch measures heart rate, and why it (hopefully) won't give you a rash | MobiHealthNews How the Apple Watch measures heart rate, and why it (hopefully) won't give you a rash | MobiHealthNews](https://www.mobihealthnews.com/sites/default/files/wp-content/uploads/2015/04/watch-heart-rate-monitor-hero.jpg)
How the Apple Watch measures heart rate, and why it (hopefully) won't give you a rash | MobiHealthNews
![Has anyone gotten a high heart rate alert on their watch from stress? Heart rate reached 150 today apparently from a challenging colleague 🤣 : r/AppleWatch Has anyone gotten a high heart rate alert on their watch from stress? Heart rate reached 150 today apparently from a challenging colleague 🤣 : r/AppleWatch](https://i.redd.it/qqnc67i1ttt91.jpg)