The ‘ahh’ sound raises the soft palate (the softer part of your upper mouth) and helps free the airways. This breathing practice is not something you do all the time but it helps retrain your body to breathe more fully and naturally, working against the ingrained habit of under-breathing. It stimulates your body to better everyday use.
REORGANISE YOUR LIFE
Smell your environment. Are you not breathing fully because you don’t want to? Bad air days need strategy; nice smells (oils, plants, flowers), ionisers, or reminders of better atmospheres (photographs of seaside or countryside).
If you do find that you are in a situation where your space is invaded (crushed on the tube or in a lift) and you feel deprived of oxygen, don’t hold your breath or take shallow breaths; focus on breathing more completely and make the best of every out breath to rid yourself of inhaled toxins and stale air.
Taken from : The Busy Body - Stress Free Posture