Mindfullness, Cortisol and Stress

PTSD: Mindfulness Exercises Improve Symptoms, Cortisol Level

Norra MacReady

May 31, 2013

Mindfulness-based stretching and deep breathing exercises (MBX) may elicit symptom relief in intensive care unit nurses with posttraumatic stress disorder (PTSD), a new study shows.

PTSD is associated with disruption of the hypothalamic-pituitary-adrenal axis, Sang Hwan Kim, PhD, and colleagues write in an article published online May 29 in the Journal of Clinical Endocrinology and Metabolism. This change, characterized in part by abnormally low levels of cortisol, "is one of the distinct neuroendocrine profiles that differentiates PTSD from other mental illnesses," they write. Citing a study showing a high level of PTSD among intensive care unit nurses, because of the stressful and often traumatic nature of their work, the authors investigated the effect of low- to moderate-intensity exercise on regulation of basal cortisol levels in this population. They included a mindfulness component to help with cognitive function and emotional regulation.

The participants were recruited through advertisements at the University of New Mexico Hospital in Albuquerque. At baseline, each volunteer completed the PTSD Checklist-Civilian version (PCL-C), in which they rated 17 symptoms on a scale of 1 (not at all) to 5 (extremely). Participants scoring at least 28 in total or at least 3 on 1 or more individual items were considered positive for PTSD and randomly assigned to either the MBX or the control group.

The 8-week MBX intervention consisted of twice-weekly hour-long sessions that included stretching and balancing movements combined with breathing and a focus on mindfulness. The authors describe mindfulness as "a quality of consciousness that is associated with control of attention and awareness promoting a direct awareness of bodily movement, sensations, and surroundings, thus often inducing positive psychological and behavioral responses." There was no specific intervention for the control group.

Of 29 nurses who met the inclusion criteria, 22 had PTSD and were assigned to either the MBX or the control group. Seven volunteers without PTSD were placed in a healthy group (BASE) to provide comparison data for cortisol levels. The researchers measured serum cortisol in all 3 groups at baseline and at weeks 4 and 8 of the study. For the MBX group, they also measured it at week 16. PTSD symptoms also were assessed at baseline and at weeks 4, 8, and 16.

Twenty-eight women and 1 man enrolled in the study, with 11 participants each in the MBX and CON groups and 7 in the BASE group. One participant in the control group dropped out because of family issues.

At baseline, the mean PCL-C score in the MBX group was 43.1 (standard deviation [SD], 11.2); it was 42.6 (SD, 12.7) in the control group. The BASE group had a mean PCL-C score of 21.8 (SD, 3.4). At 8 weeks, the mean PCL-C score in the MBX group was 24.3 (SD, 3.3), for a difference of 18.8 points (95% confidence interval [CI], 11.7 - 25.9), or a 44% decrease. In the control group, the mean 8-week PCL-C score was 41.0 (SD, 16.3), for a decrease of 1.6 points (95% CI, −6.3 to 9.5), or 3.8%. The mean changes between the groups were statistically significant (P = .01).

Mean cortisol in the MBX group was 9.6 µg/dL at baseline (SD, 4.1) and 14.6 µg/dL (SD, 5.7) at 8 weeks, for an increase of 5.1 µg/dL (95% CI, 2.0 - 8.1 µg/dL). In the control group, mean cortisol at baseline was 12.9 µm/dL (SD, 6.9); it was 13.8 µg/dL (SD, 5.7) at 8 weeks, for an increase of 0.8 µm/dL (95% CI, −2.2 - 3.8 µg/dL; P = .01 for mean changes between the groups).

The researchers found that every unit increase in cortisol was associated with a mean decrease in PCL-C score of 0.75 points, "demonstrating that as PTSD symptoms improved cortisol levels normalized." The changes in the MBX group persisted at week 16.

"During the eight-week program, some participants reported that they experienced improved sleep, stress resilience, energy levels, and emotional regulation under stress, and a resumption of pleasurable activities which they had previously discontinued. At the end of the intervention, over half of the participants expressed a desire to continue," the authors write.

Study limitations include the small number of participants and a paucity of male participants, which might limit generalizability. Nonetheless, the authors conclude, "[c]onsidering that early intervention is critical in ameliorating the development of PTSD and that PTSD symptoms are strongly correlated with the degree of distress immediately following trauma, mind-body interventions such as MBX may provide an effective non-pharmacological treatment for individuals with PTSD symptoms."

The authors have disclosed no relevant financial relationships.

J Clin Endocrinol Metabol. Published online May 29, 2013. Abstract