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Association between time of awakening and diurnal cortisol secretory activity

Edwards, Sue and Evans, Philip D. and Hucklebridge, Frank and Clow, Angela (2001) Association between time of awakening and diurnal cortisol secretory activity. Psychoneuroendocrinology, 26 (6). pp. 613-622. ISSN 0306-4530

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Official URL: http://dx.doi.org/10.1016/S0306-4530(01)00015-4

Abstract

A 12-hour diurnal profile of salivary free cortisol was measured in healthy adults (n=40) on two consecutive days. Samples were collected at timed intervals synchronised to awakening. The mean profile is characterised by a marked increase in cortisol concentration following awakening, peaking after about 30 min, and a subsequent decline over the remainder of the day. Thus two components of the diurnal cycle were examined: a) the first 45 min post-awakening (the awakening cortisol response) and b) the underlying 12 h profile from immediately until 12 h post awakening (but without the awakening response). Both of these components were analysed in two ways such as to provide an indication of overall cortisol concentration and the degree of change in cortisol concentration, i.e. the rise for the awakening response and the diurnal decline. Both components of the cortisol diurnal profile were negatively correlated with awakening time. Thus, those subjects who awoke earliest had higher levels of cortisol over the 45 min following awakening as well as throughout the rest of the day. They also displayed a more marked diurnal decline to be convergent with late awakeners at the end of diurnal measurement, 12 h following awakening. Hence the diurnal cortisol cycle, which is synchronised to awakening, is significantly related to awakening time. These findings support the notion of a close association between suprachiasmatic nucleus (SCN) control of both awakening and cortisol secretory activity.

Item Type:Article
Uncontrolled Keywords:Salivary free cortisol, Diurnal cycle, Awakening time
Research Community:University of Westminster > Social Sciences, Humanities and Languages, School of
University of Westminster > Life Sciences, School of
ID Code:150
Deposited On:30 Aug 2005
Last Modified:04 Nov 2009 14:37

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