Meditatie effect meetbaar aan melatonine
In the meditation group (n = 20), the mean level of melatonin was significantly higher than the baseline level at various times post-meditation (p < 0.001). Within the control group (n = 20), the mean level of melatonin at various times was not significantly different compared with baseline (p>0.05).
De concusie was:
Our results support the hypothesis that meditation might elevate the nighttime salivary melatonin levels. It suggests that meditation can be used as a psychophysiological stimulus to increase endogenous secretion of melatonin, which in turn, might contribute to an improved sense of well-being. 
 Liou CH, Hsieh CW, Hsieh CH, Chen DY, Wang CH, Chen JH, Lee SC. | Detection of nighttime melatonin level in Chinese Original Quiet Sitting. | J Formos Med Assoc. | 2010 Oct;109(10):694-701. doi: 10.1016/S0929-6646(10)60113-1.