I used the Oura Ring 4 to track my heart rate trend over 4 weeks — and the results surprised me

Forget the Apple Watch, Oura's heart rate data has incredible accuracy and tells me a lot about my overall health.

Amazon's Kindle Colorsoft finally convinced me to get an e-reader — but this one shortcoming is really getting under my skin

While there is no real confirmation from the e-retailer that this was true or rolled out in a recent software update, it wouldn't be the first time that Amazon has blocked users from downloading ...