Nikon Z7 User Manual page 187

D
Temperature Warnings
If the camera temperature becomes elevated, a temperature warning
will be displayed together with a count-down timer (the timer turns
red when the thirty second mark is reached). In some cases, the timer
may be displayed immediately after the camera is turned on. When the
timer reaches zero, the shooting display will turn off automatically to
protect the camera's internal circuits.
171
Technical Notes