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.
Aum actually consists of four syllables: A, U, M, and the silent syllable.
The first syllable is A, pronounced as a prolonged "awe." The sound starts at the back of your throat and you stretch it out. You will start feeling your solar plexus and chest vibrating.
The second syllable is U, pronounced as a prolonged “oo,” with the sound gradually rolling forward along your upper palate. You'll feel your throat vibrate.
The third syllable is M, pronounced as a prolonged “mmmm” with your front teeth gently touching. You will now start to feel the top of your vibrate.
The last syllable is the deep silence of the Infinite. As intelligence rises from the deep silence, you have to merge your chant from the ‘M’ to the deep silence.
Symbolically the three letters embody the divine energy (Shakti) and it’s 3 main characteristics: (1) creation, (2) preservation and (3) liberation.
Why do we chant it?
Everything in the universe is pulsating and vibrating – nothing is really standing still! The sound Om, when chanted, vibrates at the frequency of 432 Hz, which is the same vibrational frequency found throughout everything in nature.
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.