Cortisol is a chemical that our bodies create during stress. The average person has 79 micrograms/24hr of plasma cortisol.
Meditators have less plasma cortisol in unstressful situations.
Here is the research:
Ahuja MM, Karmarkar MG, Reddy S. TSH, LH, cortisol response to TRH and LH-RH and insulin hypoglycaemia in subjects practising transcendental meditation.
BEVAN, A. J. W.; YOUNG, P. M.; WELLBY, M. L.; NENADOVIC, P.; and DICKINS, J. A. Endocrine changes in relaxation procedures. Proceedingsof the Endocrine Society of Australia 19: 59 (Abstract), 1976.
JEVNING, R.; WILSON, A.; VANDERLAAN, E.; and LEVINE, S. Plasma prolactinand cortisol during Transcendental Meditation. Findings previously publishedin The Endocrine Society Program 57th Annual Meeting, New York City,18-20 June 1975, p. 257
JEVNING, R., and WILSON, A. F. Acute decline in adrenocortical activityduring Transcendental Meditation. Department of Medicine, University ofCalifornia at Irvine, Orange, California, U.S.A., 1977.
JEVNING, R.; WILSON, A. F.; and DAVIDSON, J. M. Adrenocortical activityduring meditation. Hormones and Behavior 10(1): 54-60, 1978.
SUBRAHMANYAM, S., and PORKODI, K. Neurohumoral correlates of TranscendentalMeditation. Journal of Biomedicine 1: 73-88, 1980.
