Shortly after<unk> , a sharp 38–75% (average 50%) increase occurs in the blood level of<unk>  in about 77% of healthy people of all ages. The average level of salivary<unk>  upon waking is roughly 15 nmol/l; 30 minutes later it may be 23 nmol/l, though there are wide variations. The<unk>  reaches a maximum approximately 30 minutes after<unk>  though it may still be heightened by 34% an hour after waking. The pattern of this<unk>  to waking is relatively stable for any individual. Twin studies show its pattern is largely genetically determined since there is a heritability of 0.40 for the mean<unk>  increase after<unk>  and 0.48 for the area under the<unk>  rise curve. Normally, the highest<unk>  secretion happens in the second half of the night with peak<unk>  production occurring in the early morning. Following this,<unk>  levels decline throughout the day with lowest levels during the first half of the night.<unk>  is independent of this circadian variation in HPA axis activity; it is superimposed upon the daily rhythm of HPA axis activity, and it seems to be linked specifically to the event of<unk> .<unk>  provides an easy measure of the reactivity capacity of the HPA axis.
Cortisol awakening response
Optokinetic response
Dexamethasone suppression test
Electrodermal activity
Basal metabolic rate
Alpha cell hyperplasia
Basal rate
Metabolic window