Changes in Diurnal Salivary Cortisol Levels in Response to an Acute Stressor in Healthy Young Adults

Abstract

Knowledge of the diurnal cortisol response to acute stress in healthy individuals can help us better understand the physiological and health effects of chronic stress. To compare the diurnal patterns of cortisol secretion of 15 medical students 2 weeks before a major written examination (control phase) and 2 weeks later at the time of the examination (acute stress phase). Interrupted time series within-subjects. During the acute stress phase, less cortisol was secreted over the course of the day, as demonstrated by a more prolonged and steeper decline in cortisol levels. In addition, higher cortisol levels were present in the evening. Despite these changes in the usual diurnal pattern, overall exposure to cortisol remained the same for both phases. The results of this study suggest that specific adaptations to the diurnal pattern of cortisol are made in the face of acute stress, important information for understanding cortisol regulation in health and illness.