Effects of the Transcendental Meditation program on adaptive mechanisms: changes in hormone levels and responses to stress after 4 months of practice.
C R MacLean, Kenneth G Walton, S R Wenneberg, Debra K Levitsky, J P Mandarino, R Waziri, S L Hillis, Robert H Schneider
Psychoneuroendocrinology May 1997 DOI: 10.1016/s0306-4530(97)00003-6 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Prospective, random assignment study Peer reviewed |
|---|---|
| Intervention | Stress education control condition |
| Duration | 4 months |
| Topics | Meditation |
| Key points | After four months, TM practitioners showed decreased basal cortisol and average cortisol across a stress session, and increased cortisol responsiveness to stressors, compared with controls. Changes in TSH, GH, and testosterone also differed between groups, with cortisol and testosterone results supporting the idea that TM reverses effects of chronic stress. |
Abstract
Stress has been implicated in both somatic and mental disorders. The mechanisms by which stress leads to poor health are largely unknown. However, studies in animals suggest that chronic stress causes high basal cortisol and low cortisol response to acute stressors and that such changes may contribute to disease. Previous studies of the Transcendental Meditation (TM) technique as a possible means of countering effects of stress have reported altered levels of several hormones both during the practice and longitudinally after regular practice of this technique. In this prospective, random assignment study, changes in baseline levels and acute responses to laboratory stressors were examined for four hormones-cortisol, growth hormone, thyroid-stimulating hormone and testosterone-before and after 4 months of either the TM technique or a stress education control condition. At pre- and post-test, blood was withdrawn continuously through an indwelling catheter, and plasma or serum samples were frozen for later analysis by radioimmunoassay. The results showed significantly different changes for the two groups, or trends toward significance, for each hormone over the 4 months. In the TM group, but not in the controls, basal cortisol level and average cortisol across the stress session decreased from pre- to post-test. Cortisol responsiveness to stressors, however, increased in the TM group compared to controls. The baselines and/or stress responsiveness for TSH and GH changed in opposite directions for the groups, as did the testosterone baseline. Overall, the cortisol and testosterone results appear to support previous data suggesting that repeated practice of the TM technique reverses effects of chronic stress significant for health. The observed group difference in the change of GH regulation may derive from the cortisol differences, while the TSH results are not related easily to earlier findings on the effects of chronic stress.