Katja Petrowski1, Bjarne Schmalbach2, Tobias Stalder3. 1. Medical Psychology and Medical Sociology, Department of Psychosomatic Medicine and Psychotherapy, University Medical Center of the Johannes Gutenberg University, Mainz, Germany. Electronic address: kpetrows@uni-mainz.de. 2. Department of Psychosomatic Medicine and Psychotherapy, University Medical Center of the Johannes Gutenberg University, Mainz, Germany. 3. Institute of Psychology, University of Siegen, Germany.
Abstract
BACKGROUND: Earlier evidence indicated an association between chronotype and the cortisol awakening response (CAR). However, these earlier data were collected without objective control for participant compliance being available, which, following recent guidelines, is considered critical for ensuring data validity. Here, we are seeking to replicate these earlier findings within a well-controlled sleep laboratory set up. METHODS: The sample consisted of 103 young males, including 12 participants defined as 'evening' (MEQ < 41) and 20 participants defined as 'morning type' (MEQ > 59) types. All participants slept for one night in a sleep laboratory and were wakened at 6:30 AM the next morning. Saliva samples for the assessment of the CAR were collected under strict supervision at 0, 15, and 30 min post-awakening. RESULTS: Significant effects of chronotype emerged consistently from both dimensional analyses across the entire sample and from comparisons between morning vs. evening type. Overall, greater morningness was associated with an increased cortisol level upon awakening (S1) as well as with a greater overall cortisol output (AUCG), however, it was not associated with the CAR (AUCI). DISCUSSION: Our data corroborate earlier evidence by showing that, under well-controlled sleep-laboratory conditions, chronotype is related to an altered cortisol secretion over the post-awakening period with no association with the CAR. However, the results have to be replicated since it is only a single day study design.
BACKGROUND: Earlier evidence indicated an association between chronotype and the cortisol awakening response (CAR). However, these earlier data were collected without objective control for participant compliance being available, which, following recent guidelines, is considered critical for ensuring data validity. Here, we are seeking to replicate these earlier findings within a well-controlled sleep laboratory set up. METHODS: The sample consisted of 103 young males, including 12 participants defined as 'evening' (MEQ < 41) and 20 participants defined as 'morning type' (MEQ > 59) types. All participants slept for one night in a sleep laboratory and were wakened at 6:30 AM the next morning. Saliva samples for the assessment of the CAR were collected under strict supervision at 0, 15, and 30 min post-awakening. RESULTS: Significant effects of chronotype emerged consistently from both dimensional analyses across the entire sample and from comparisons between morning vs. evening type. Overall, greater morningness was associated with an increased cortisol level upon awakening (S1) as well as with a greater overall cortisol output (AUCG), however, it was not associated with the CAR (AUCI). DISCUSSION: Our data corroborate earlier evidence by showing that, under well-controlled sleep-laboratory conditions, chronotype is related to an altered cortisol secretion over the post-awakening period with no association with the CAR. However, the results have to be replicated since it is only a single day study design.
Authors: Maira Karan; Danny Rahal; David M Almeida; Julienne E Bower; Michael R Irwin; Heather McCreath; Teresa Seeman; Andrew J Fuligni Journal: Psychoneuroendocrinology Date: 2021-07-31 Impact factor: 4.693