The Shamatha Project at the University of California/Davis (California, USA) is a comprehensive long-term, control-group study of the effects of meditation training on mind and body. Tonya Jacobs and colleagues used a questionnaire to measure aspects of mindfulness among a group of volunteers before and after an intensive, threemonth meditation retreat.

They also measured cortisol levels in the volunteers’ saliva. During the retreat, a Buddhist scholar and teacher trained participants in such attention skills as mindfulness of breathing, observing mental events, and observing the nature of consciousness. Participants also practiced cultivating benevolent mental states, including loving kindness, compassion, empathic joy and º. At an individual level, there was a correlation between a high score for mindfulness and a low score in cortisol both before and after the retreat. Individuals whose mindfulness score increased after the retreat showed a decrease in cortisol. Scores on the mindfulness questionnaire increased from pre- to post-retreat, while levels of cortisol did not change overall. The study authors submit: “These data suggest a relation between self-reported mindfulness and resting output of the hypothalamic-pituitary-adrenal system.”


  1. [Jacobs, Tonya L.; Shaver, Phillip R.; Epel, Elissa S.; Zanesco, Anthony P.; Aichele, Stephen R.; Saron, Clifford D.; et al. “Self-Reported Mindfulness and Cortisol During a Shamatha Meditation Retreat.” Health Psychology, Mar. 25, 2013.