Pranayama - the yoga of breathing
It's something we do 24/7 unconsciously - breathing. We simply take it for granted unless or until something happens to affect it. Then we become very aware of our breath indeed, just how much we rely on it and how uncomfortable it can be to not breathe breathe fully. But even on a good day, we tend to breathe very shallowly, in and out of just the top part of the lungs.
Pranayama is the practice of conscious breathing - it comes from two sanskrit words, prana meaning the fundamental life force/energy, and yama meaning to control. So this is more than just inhaling and exhaling air; this is a technique, a science, for expanding and chaneling the life force. Anyone can practice, and you can practice it anywhere.
So what are the benefits of pranayama?
Physically,there are a number of things that take place when we breathe fully and deeply. The cells in the body get suffused with more oxygen and more carbon dioxide gets pumped out. A sort of cellular detox and re-energise! The diaphragm also gets a good workout. Thirdly, with the diaphragm exercising up and down (we don't breathe in and out, by the way, we technically breathe down and up!), the thoracic spine, the section with the ribs attached, gets a good massage. This is important because we don't flex much with that part of the spine, being more bendy in the lumbar area lower down.
Energetically, we are purifying the energy channels (called nadis) around the body, apparently we have 72,000! If we are following Patanjali's Yoga Sutras and his Eight Limbs of Yoga, pranayama comes after asana. This means that having opened and activated energy channels during the yoga posture sequence, the breathing practice purifies them, getting the body ready for meditation and/or relaxation.
Spiritually, conscious breathing is de-stressing and helps clear the mind. By focusing only on the breath, the mind can rest, giving a sense of calm and peace. Often pranayama leaves a sense of clarity. Practiced regularly, it can induce an inner stillness that can take us deep within, especially if followed by meditation.
There are several breathing techniques, one of which is nadi shodhana, alternate nostril breathing. There are a couple of stages that build up to full alternate nostril breathing - the video below explains the First Tecnhique (ref Hatha Yoga Pradipika).
So, go on and take a breath!