Because all brain injuries are different, so is concussion recovery. Most people with mild injuries recover fully, but it can take time. Some symptoms can last for days, weeks, or longer. In general, recovery is slower in older persons. Also, persons who have had a concussion in the past may find that it takes longer to recover from their current injury.
WatchOS is the operating system (OS) that runs on every Apple Watch - basically, the watch equivalent of iOS, which you'll find on iPhones and iPads. Operating systems essentially sit between the hardware - in this case, the Apple Watch - and the apps that you download. Everything that you do on your Watch is possible because of WatchOS. It's the menus that you scroll through, to load up apps and tweak the Watch's settings. It's the clock faces and other built-in features that you see when you turn your Watch on.
The Apple Watch is about to get its first update in the form of watchOS 2, a software update that is going to add a lot of new features to the Apple Watch. Apple has revealed that watchOS 2's release date will be 16 September, and in addition we're getting some fancy new Apple Watch models and gorgeous new straps.