Psychoneuroendocrinology 29 (2004) 516–528 www.elsevier.com/locate/psyneuen Differences in cortisol awakening response on work days and weekends in women and men from the Whitehall II cohort Sabine R. Kunz-Ebrecht a1 , Clemens Kirschbaum b , Michael Marmot a , Andrew Steptoe a,* a University College London, Department of Epidemiology and Public Health, 1–19 Torrington Place, London WC1E 6BT, UK b Institute of Experimental Psychology II, University of Du ¨sseldorf, Du ¨ sseldorf, Germany Received 14 February 2003; received in revised form 31 March 2003; accepted 3 April 2003 Abstract It is thought that the salivary cortisol awakening response can serve as a reliable marker of hypothalamic–pituitary–adrenocortical activity. Response magnitude might be influenced by stress, but results of studies on work-related stress have been inconclusive. Non-compliance with the sampling schedule is a potential confounding factor that has rarely been controlled. The objective of the study was to determine whether the cortisol awakening response is greater on a work day than on a weekend day, and whether responses vary with gender and socioecon- omic position. Compliance was controlled by excluding participants who reported a delay of more than 10 min between waking up and taking the first saliva sample. Data were collected from 196 men and women aged 47 to 59 years drawn from the Whitehall II cohort of British civil servants, with free salivary cortisol sampled immediately after waking up and 30 min later on 2 days. Data on stress, perceived control and happiness over the remainder of the day, and on sleep quality, time of waking, and health behaviour were also obtained. The awakening response was lower in non-compliant participants than in compliant ones, so non- compliant participants were excluded from further analyses. Salivary cortisol levels on waking did not differ by gender or socioeconomic position, or between work and weekend days. However, the cortisol awakening response (defined as the difference between waking and 30 min later) was greater on work than weekend days (mean increases 10.5 and 3.7 nmol/l, P * Corresponding author. Tel.: +44-20-7679-1804; fax: +44-20-7916-8542. E-mail address: a.steptoe@ucl.ac.uk (A. Steptoe). 1 Present address: Department of Social Epidemiology, Institute for Therapy Research, Munich, Ger- many. 0306-4530/$ - see front matter  2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0306-4530(03)00072-6