Mindful Movement Normalizes Hormone Levels: MBX-12 at Harvard Part 4
Presented for Introduction to Lifestyle Medicine, Harvard Extension School: PSYC E-1037.
Notes by Sang H. Kim, Ph.D.
These notes are intended as additional resources for my brief presentation on October 21, 2014, for Introduction to Lifestyle Medicine, which is a Psychology Extension course at Harvard University. This is based on my personal notes while preparing for the research and the published research findings. I blog about them as a series. Read Part 1, Part 2, Part 3.
Current research has succeeded in identifying treatments that lead to PTSD symptom reduction and also in quantifying the neurobiological markers associated with the severity of the symptoms.
For example, lasting neurobiological changes in combat veterans with PTSD correlate with the manifestation of specific symptoms including: increased 24-hour urinary norepinephrine positively correlated with intrusive traumatic memories; and low 24-hour urinary cortisol levels correlated with a failure of normal memory consolidation.
Despite the advances made in the areas of pharmacology, psychotherapy, and biology as they relate to PTSD, we still lack a complete understanding of the dysfunction of the autonomic nervous system in PTSD, and residual symptoms remain problematic.
The goal of our study was to uncover the relationship between cortisol and exercise-induced PTSD symptom reduction. Because this approach is rooted neither in psychotherapy nor in pharmacology, it represents a significant departure from the status quo and has the potential to lead to the development of an effective new complementary therapy for this common and devastating disorder.
Studies have shown that mindfulness-based exercise interventions lead to symptom reduction in patients with PTSD. For example, Vietnam veterans who practiced yoga for six weeks showed a significant reduction in depression, sleep disturbances, flashbacks, anger outbursts, and emotional dis-regulation.
What is less clear is the impact of exercise on the neurobiological anomalies associated with PTSD such as reduced cortisol level and increased catecholamine levels.
It has been established that individuals with chronic PTSD suffer from low cortisol levels; that low cortisol levels are correlated with PTSD symptom severity; and that cortisol levels may change in relation with symptom modification.
In healthy people, we know that immediately following exercise, cortisol levels are elevated; and that after exercise at a lower work rate (55 % VO2max) for a longer duration, plasma cortisol concentrations rise higher than those observed at a higher work rate (80 % VO2max).
The question that I had was whether the resting Ante Meridiem (AM) plasma cortisol levels increase in individuals with PTSD as a result of exercise, and how an exercise-induced increase in cortisol relates to PTSD symptom reduction.
There is considerable research to support the neuroprotective benefits of exercise for people with chronic stress. Moderate-intensity exercise has been shown to have neurobiological effects on chronic stress-related symptoms including improved regulation of the serotonergic system, counteraction of degradation of the hippocampus caused by chronic stress, reduction of neurobiological sensitivity to stress, and normalization of catecholamine levels.
There is sufficient data to suggest the positive relationship between exercise and PTSD symptom reduction. More well-established is the link between cortisol levels and PTSD symptom severity. For example, among veterans who served in Vietnam, individuals with a current diagnosis of PTSD had significantly lower adjusted plasma cortisol levels than individuals who did not have a diagnosis of PTSD.
To be continued in Part 5: 21 Grant Writing Action Items.