Tantra or yoga. Clinical studies, section 1: Yoga

Several clinical studies show how exercises in Vedic traditions, such as Yoga, or Theravada or Mahayana Buddhisms as well as tantric practices have a significant psychobiological impact. This study seeks the neurophysiological correlate of the practices called tantric and non-tantric meditations through a qualitative systematic review of the data collected. First the non-tantric meditations results were checked, then the tantric meditations data was collected, finally both were compared and we hereby report the results arranged in three sections. In this first section, it was found that non-tantric meditations create a better relaxation response with increased parasympathetic activity and inhibition of the sympathetic system, which induces a deep rest hypometabolic state where the practitioner remains awake and their attention, in "tonic alertness" with the symptoms corresponding to such hypometabolic state -hypotonia, decreased oxygen consumption, heart rate and blood lactate concentration- change in normal endocrine function, increased phenylalanine concentration in advanced meditators, increased plasma prolactin levels, a five-fold increase in arginine vasopressin plasma levels, while thyroid stimulating hormone decreases chronically and acutely. This research opens the door to conduct longitudinal clinical studies, to confirm the long-term beneficial effects of practices and establish mechanisms to counteract the unwanted side-effects herein presented.