Om is a mantra, or vibration, that is traditionally chanted at the beginning and end of yoga sessions. Coming from Hinduism and Yoga, the mantra is considered to have high spiritual and creative power but despite this, it is a mantra that can be recited by anyone. It’s both a sound and a symbol rich in meaning and depth and when pronounced correctly it is actually AUM. Symbolically the three letters embody the divine energy (Shakti) and it’s 3 main characteristics: (1) creation, (2) preservation and (3) liberation. As such AUM is the basic sound of the universe; so by chanting it we are symbolically and physically tuning in to that sound and acknowledging our connection to all other living beings, nature and the universe.
In addition the vibrations and rhythmic pronunciation also have a physical affect on the body by slowing down the nervous system and calming the mind similar to meditation. When the mind is relaxed, your blood pressure decreases and ultimately the health of your heart improves.
Finally it is also a way to delineate the time of our practice from the rest of our day and signify that this is a special time in which to care for ourselves and practice being mindful. All in all, beginning and/or ending your yoga practicing with AUM helps to connects us to our practice in a deeper way than just with physical postures. Reference: https://www.mindbodygreen.com/0-7565/om-what-is-it...