Note: Sit with a tall spine, soft shoulders, and relax the features of your face. Do not strain. You can practice one technique on its own, or all 3 together as a sequence. Repeat each technique for 2-5 minutes.
About: Imagine taking the deepest, fullest, slowest breath and then releasing it with the same mindfulness. That is the essence of the Three Part Breath. This technique incorporates diaphragmatic breathing which influences the Vagus nerve and invokes the relaxation response. 
Place your left hand on your heart and your right hand on your lower abdomen. This facilitates your ability to feel the breath.
Inhale through your nostrils, breathing downwards until you feel your abdomen inflate like a balloon. This sensation is your diaphragm moving downward creating more space for your lungs to expand to their optimal capacity. Do this for a count of 4 seconds.
Continue inhaling into your rib cage until you feel it widen like an accordian opening. Do this for a count of 2 seconds.
Continue inhaling into your chest until you feel it lifting towards your collarbones. Do this for a count of 2 seconds.
Slowly exhale through your nostrils, feeling your chest and your ribcage empty/contract. Do this for a count of 6 seconds.
Continue exhaling, gently drawing your navel back toward your spine feeling your abdominal muscles help to press out the last bit of breath. Do this for a count of 2 seconds.
Hold at the bottom of your exhale for 2 extra counts before inhaling again. It’s been shown that longer exhales help to activate the relaxation response.
Along with diaphragmatic breathing, you can increase the relaxation response by further stimulating the Vagus nerve. Create a slight constriction in the back of your throat as you breathe. This slightly activates the vocal cords and creates a whispery soft “hahhh” sound to your breath. You can learn this by exhaling as if you are trying to fog a mirror with your breath (to create the feeling of constriction in your throat). From there, close the mouth and maintain that gentle pressure in the throat as you inhale and exhale out of the nose. This is called Ujjayi pranayam.
About: In this breathing technique you use the help of your fingers to alternate breathing in and out of one nostril at a time which can bring a sense of balance to the mind and body.
Bring your right hand into Pran mudra by connecting your thumb, ring and pinky finger into a circle while keeping your pointer and middle fingers touching and straight.
From there, rest your right thumb to your right nostril. Rest your right pointer and middle finger on the centre of your forehead. Rest your ring and pinky finger as a unit on your left nostril.
Gently close your left nostril with your ring-pinky finger unit. Inhale through your right nostril, then close it with your thumb. Open and exhale slowly through your left nostril.
Keep the left nostril open, inhale, then close it, and open and exhale slowly through the right.
Make sure you are breathing slowly and deeply. Studies have shown that deep breathing influences the body-brain loop and activates the relaxation response. 
This is one cycle. Repeat 5 -10 times, then release the hand mudra and go back to normal breathing.
About: Think of the buzzing sound a bee makes. This style of breathing recreates that sound to help silence the outer world and focus your mind. The vibrations of humming stimulate the Vagus nerve which passes through the vocal cords and the inner ear. As stated previously, Vagus nerve stimulation has been shown to reduce the body’s response to stress.
Take a slow, deep breath in and for the entire length of your exhalation, make a medium-pitched humming sound in the throat.
Notice how the exhalation naturally becomes longer than the inhale.
Feel the sound waves gently vibrate your sinuses, teeth and tongue.
Imagine the sound is penetrating your brain and silencing your thoughts.
To intensify the effects you can add a variation of Shanmukhi mudra.
Bhramari encourages Pratyahara (the turning of the senses inward).
Close your eyes, and use your thumbs to block your ear canal by gently pushing on the tragus of each ear (the bump of cartilage on the cheek side).
Place your fingers on your forehead.
Continue the humming sound on your exhalations.
Repeat 6 or more times.
Lauren Dee Teaches Yoga Online and at International Yoga Retreats. Find Her on Instagram @laurendeeyoga or on Her Website laurendeeyoga.com to Receive Her Free eBook “Spirit Sweat” a How-To Handbook that Unites the Physical and Philosophical Practice of Yoga.