mouth breathing
Noun
Meaning
(medicine) Long-term breathing through the mouth, often caused by an obstruction to breathing through the nose.
Used other than figuratively or idiomatically: breathing through the mouth.
Source: en.wiktionary.orgExamples
Snoring can be caused by a number of things, including the sleep position, alcohol, medication, anatomical structure of the mouth and throat, stage of sleep, and mouth breathing.
Holding your breath, rapid breathing, shallow breathing, mouth breathing.