I’ve found no more eloquent response to the question on how to breathe “correctly” than from Carola Speads in her book “Ways to Better Breathing. (Read also my previous post about Carola Speads)
„There is no such thing as one right and best way to breathe at all times. We breathe differently and many ways of breathing can be appropriate. Walking demands a different type of breathing than sleeping, the attention in an important dialogue has a different breath quality than a casual conversation. Anger makes us breathe differently than peaceful silence. A certain type of breathing may be appropriate to one situation but not to another. There is no optimal way to breathe. Breathing is an involuntary self-regulating function. One cannot practice something that regulates itself. Only voluntary actions can be practiced repeatedly. We can‘t „do“ the breath the way we do a movement. The breath can only be enlivened and encouraged to change itself on its own accord by itself.“