Effects of the Transcendental Meditation program on adaptive mechanisms: changes in hormone levels and responses to stress after 4 months of practice.
Level 2 - randomized trial
Individual randomized controlled trial comparing Transcendental Meditation to an active stress education control.
PubMed 9226731 · doi:10.1016/s0306-4530(97)00003-6
What was done
In a prospective randomized controlled trial, participants were randomly assigned to 4 months of either the Transcendental Meditation (TM) program or a stress education control condition. Blood was sampled continuously via an indwelling catheter to measure baseline levels and acute responses to laboratory stressors for four hormones—cortisol, growth hormone (GH), thyroid-stimulating hormone (TSH), and testosterone—via radioimmunoassay at baseline and at 4-month follow-up.
What was found
The abstract reports directional changes and trends but provides no specific numerical values, standard deviations, or exact p-values. In the TM group, basal cortisol and average cortisol levels across the stress session decreased over 4 months, whereas cortisol responsiveness to acute stressors increased relative to controls. Baselines and/or stress responsiveness for TSH and GH, as well as baseline testosterone, showed opposing trajectories between the TM and control groups.
Why it matters
The findings suggest that regular TM practice may modify neuroendocrine stress pathways by lowering resting cortisol while preserving or enhancing acute physiological stress reactivity.
Limits
The abstract does not disclose participant sample size, demographics, or exact numerical effect sizes and confidence intervals. Long-term durability beyond 4 months and direct clinical health outcomes were not evaluated.
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