One verse

Srimad Bhagavatam 4.29.71

4.29.71

सुप्तिमूर्च्छोपतापेषु प्राणायनविघातत: । नेहतेऽहमिति ज्ञानं मृत्युप्रज्वारयोरपि ॥ ७१ ॥

supti-murcchopatapesu pranayana-vighatatah nehate ’ham iti jnanam mrtyu-prajvarayor api

supti
in deep sleep
murccha
fainting
upatapesu
or in great shock
prana-ayana
of the movement of the life air
vighatatah
from prevention
na
not
ihate
thinks of
aham
I
iti
thus
jnanam
knowledge
mrtyu
while dying
prajvarayoh
or during high fever
api
also.

When the living entity is in deep sleep, when he faints, when there is some great shock on account of severe loss, at the time of death, or when the body temperature is very high, the movement of the life air is arrested. At that time the living entity loses knowledge of identifying the body with the self.