Cortisol awakening response

[2] Shortly after awakening, a sharp 38–75% (average 50%) increase occurs in the blood level of cortisol in about 77%[3] of healthy people of all ages.

[31] This is a synthetic glucocorticoid and this inhibition allows the detection of the presence of negative feedback from circulating cortisol that controls to ACTH-secreting cells of the pituitary.

[4] The function of cortisol awakening response is unknown but it has been suggested to link with a stress-related preparation in regard to the upcoming day by the hippocampus.

[37] One hypothesis is: "that the cortisol rise after awakening may accompany an activation of prospective memory representations at awakening enabling individual's orientation about the self in time and space as well as anticipation of demands of the upcoming day... it is tempting to speculate that for the CAR, anticipation of these upcoming demands may be essential in regulating the CAR magnitude for the particular day.

The hippocampus is, besides its established role in long-term memory consolidation, involved in the formation of a cohesive construct and representation of the outside world within the central nervous system processing information about space, time and relationships of environmental cues.