Breathing through the nose has many benefits, whilst breathing through the mouth, has many negatives.
There are some researchers who believe that mouth breathing and associated hyperventilation causes or exacerbates asthma, high blood pressure, heart disease, and many other medical problems.
It is strongly recommended, whenever possible - deviated septum and small nostrils may make it impractical or more difficult – to practice nose breathing 24/7. Let us note a few direct aspects: