Exploring the interplay of glucocorticoids, daily timing, sleep, and psychology-based task performance

Human chronotypes can be defined as the natural preference for specific wake and sleep times. They are a consequence of the circadian clock individual periods. Cortisol is a key mediator for the rhythmic expression of circadian signals in almost all tissues and strictly regulated by the hypothalamic-pituitary-adrenal (HPA) axis. Diseases affecting HPA signaling might therefore have important consequences on chronotype and connected performance.20 patients with autoimmune adrenilitis and 40 control subjects of comparable age (54.53±18.42 vs 48.56±15.5 years) and sex (14f/6m vs 32f/8m) were assessed for their chronotypes using the Munich Chronotype Questionnaire, were subjected to five different psychology-based tasks (four times) and were requested to wear an actimetry device for 12 weeks. We observed high variability in sleep onset (F statistic =1.876, p<0.001) and sleep duration (F statistic =2.496, p<0.001) for patients in comparison to controls. The mean value for sleep onset were also observed to be earlier for patients (mean = 131.708minutes) in comparison to controls (mean = 155.803 minutes) (one-way ANOVA, statistic=29.842, p <0.001). Chronotypes of patients showed high variability in comparison to controls (F statistic =2.192, p=0.008). Lower performance was observed for patients in comparison to controls of the earlier chronotype, in tests that measured attention(p <0.05), emotion recognition (p <0.05) and aesthetic sensitivity (p <0.05). In addition, the patients also exhibit a numerically later sleep onset on the weekends, which is not compensated by increased duration of sleep on the next day.