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Updated: May 4, 2026

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures
Published on: November 11, 2016
The biological clock modulates the human cortisol response in a multiplicative fashion
Maan van de Werken1, Sanne H Booij, J Esi van der Zwan
1Department of Chronobiology, Centre for Life Sciences, University of Groningen , Groningen , the Netherlands.
Abstract:
Human cortisol levels follow a clear circadian rhythm. We investigated the contribution of alternation of sleep and wakefulness and the circadian clock, using forced desynchrony. Cortisol levels were best described by a multiplication of a circadian and a wake-time component. The human cortisol response is modulated by circadian phase. Exposure to stress at an unnatural phase, as in shift work, is predicted to result in abnormal cortisol levels. Health of shift workers may therefore improve when stress is reduced at times when the clock produces high stress sensitivity.
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