Breathing is a vital component of singing.
But the way we breathe when singing is different than the way we breathe in everyday life, requiring us to use our respiratory muscles in new and different ways.
The goal when singing is to have breath control and good breath support.
Breath control means being able to inhale quickly and exhale slowly throughout the phrase while maintaining good posture. (source)
Breath support means using other muscles (e.g. abdomen, back) to support the work of the lungs and foster better tone production and the ability to sing longer phrases. (source)
