eli5: why do most, if not all, breathing techniques specify ‘out through the mouth’?

Question

i can understand in ‘through the nose’, since dust and other bits can be blocked by the nose hairs and mucus, and apparently the air is more likely to warm up when passing through the nose first, reducing irritation of the throat.

but what difference, if any, does exhaling through the mouth make?

In: 676

Answer 1

A therapist I know says that an inhale through the nose and then a longer exhale through the mouth causes a parasympathetic response in the body that causes it to relax.