Ujayi Pranayama or victorious breath is a classic pranayama practice, known for its soft soothing sound quality like breaking ocean waves. This breath has such a calming effect as the vagus nerve is stimulated enhancing a relaxation response. It is the perfect breath-work on your yoga mat.
Alternate nostril breathing or Nadi Shodhana is the practice of alternating between the right and left nostrils as you inhale and exhale. It unblocks and purifies the nadis, which yogis believe are energy passages that carries life force and cosmic energy. This is an exceptionally powerful breath-work that can literally calm the nervous system.
Breath retention or Kumbhaka Pranayama is a full 10 second hold after fully inhaling and then taking one more small sip of air in. Holding the breath helps to increase pressure inside the lungs giving them time to expand so their capacity increases ultimately sending more oxygen throughout the body.
Breath of Fire or Kapalabhati Pranayama is a rapid breathing technique that energizes and activates the sympathetic nervous system. This is a great breath to practice as long as you are not under stress.
When practice yoga remember to inhale when opening and lifting the chest and exhale when bending forward or twisting.