Reference

MacLean, R.K., Walton, K.W., Wenneberg, S.R., Levitsky, D.K., Mandarino, J.V., Waziri, R., Hillis, S.L. and Schneider, R.H. Effects of the Transcendental Meditation Program on adaptive mechanisms: Changes in hormone levels and responses to stress after four months of practice. Psychoneuroendocrinology vol 22(4), 1997

Summary

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 four months of either the TM technique or a stress education control condition. At pretest and posttest, blood was continuously withdrawn through an indwelling catheter, and plasma or serum samples were frozen for later analysis by radioimmunoassay.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 four months. In the TM group but not the controls, basal cortisol level and average cortisol across the stress session decreased from pretest to posttest. 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 easily related to earlier findings on the effects of chronic stress.

This study was supported by a grant from the National Institutes of Health.