What is Salivary Cortisol — Afternoon?
The afternoon salivary cortisol reflects the continued physiological decline of cortisol through the second half of the active day, now at approximately 20–30% of the morning peak value. This time point sits within the zone of declining but still biologically active cortisol secretion — providing energy substrate, anti-inflammatory tone, and metabolic homeostasis for the afternoon activity period while initiating the transition toward the evening nadir. Afternoon cortisol is particularly responsive to psychological and physical stressors — acute stress at this time of day produces a proportionally larger relative rise above the low afternoon baseline than the same stressor applied in the morning.