Influence of mindfulness practice on cortisol and sleep in long-term and short-term meditators

There is growing scientific interest in assessing the biological correlates of non-pharmacological interventions such as mindfulness. Examinations of the beneficial effects of mindfulness on hypothalamus-pituitary-adrenocortical system activity (HPA SA) and sleep are sparse. The aim of the present study was to explore the impact of long- and short-term meditation experience on HPA SA and sleep.

There were 20 participants, 9 of whom had long-term experience in meditation (mean = 264 months) and 11 novices. Novices underwent an 8-week course in Mindfulness-Based Stress Reduction (MBSR), and cortisol samples were taken in the lab at the beginning and end of the course. To assess the cortisol awakening response, 4 morning cortisol samples were collected. Sleep and mindfulness were assessed by self-rating questionnaires.

Among participants with long-term meditation experience, morning cortisol decreased with length of experience. For novices, after an 8-week introductory MBSR course, morning cortisol levels had decreased, while both sleep and self-attribution of mindfulness significantly improved. Cortisol levels did not, however, change between the beginning and end of individual MBSR sessions.

The pattern of results lends support to the view that MBSR/meditation has a favorable influence both on biomarkers of stress regulation, such as cortisol secretion, and on sleep.