Tradition, Science and Practice of Om Dhyana (Meditation): A Comprehensive Review.

Om is considered the primordial sound of the universe and is highly regarded in the Indian tradition. Dhyana (meditation) on the Om mantra, a yogic mento-spiritual practice, can be performed through various methods such as verbal/mental chanting, listening to it, and gazing or visualization. Several health-related benefits are reportedly associated with it. The study aimed to qualitatively analyze all the health-related benefits from the existing scientific literature. A systematic advance search was performed on PubMed, Scopus, and Web of Science databases which yielded 101 studies, and 5 additional studies were identified through searching citations. After removing duplicates and screening the relevant studies, 20 studies were finalized for review. Studies were grouped according to their reported effects and analyzed qualitatively by Joanna Briggs Institute (JBI) checklist for Quasi-Experimental Studies and Randomized Controlled Trials. Out of 20 reviewed studies, 17 were quasi-experimental, while 3 were randomized controlled studies. 11 studies monitored brain functions, 8 assessed cardiac functions, and 1 evaluated pulmonary functions. The duration of most studies (18 studies) assessing the effect of Om chanting was ≤3 days. Studies reported increased alpha and theta activities of brain waves, enhanced cognition, relaxation, greater heart rate variability, and autonomic balance. The overall quality of the studies (as per the JBI tool) was fair (18 out of 20 studies). Overall, a tendency towards balancing and improving the brain and cardiac functions was seen through enhanced relaxation and awareness. However, studies with robust designs exploring the long-term effects of Om meditation on a larger population are needed.