It was necessary recently to restart the watch Apple Watch 2, which began to visually slow to work.
1) The first thing you need to try to turn them off and turn it on.
To do this, the clock should be disconnected from the charger, then you need to press and hold the side button until the “Off” slider appears, on which you want to drag your finger.
After switching off, you must press the side button again to turn the clock on.
2) There is also the possibility of forced restart, which can be done for example when the clock does not respond.
To do this, press the side button and the wheel at the same time, then hold them for about 10 seconds until the Apple logo appears.
Forced restart can not be done when updates are being installed or they are launched (the Apple logo is displayed).
See also the video: