iPhone X Overheating

Phone overheated. Nothing running. Nothing would work. Phone kept closing the app, showing black screen with time out/WiFi circle in the middle of the screen. Couldn’t even do an update.

Appears mine was caused by the Activity app. Reset the phone and activity app disappeared, phone cooled down. Allowed me to do an update (11.2.1)which restored the activity app.

Got solution from here http://recomhub.com/blog/iphone-x-overheating-solution/