Should I breath through my mouth or my nose? I’m confused?

The Importance of Breathing Through Your Nose

• Except for emergencies, our breathing was designed to take place mainly through our nose. When we breathe through our nose, the hairs that line our nostrils filter out particles of dust and dirt that can be injurious to our lungs. If too many particles accumulate on the membranes of the nose, we automatically secret mucus to trap them or sneeze to expel them. The mucous membranes of our septum, which divides the nose into two cavities, further prepare the air for our lungs by warming and humidifying it.
• There is another important reason for breathing through the nose. This has to do with maintaining the correct balance of oxygen and carbon dioxide in our blood. When we breathe through our mouth we usually inhale and exhale air quickly in large volumes. This often leads to a kind of hyperventilation (breathing excessively fast for the actual conditions in which we find ourselves). It is important to recognize that it is the amount of carbon dioxide in our blood that generally regulates our breathing.
• Research has shown that if we release carbon dioxide too quickly, the arteries and vessels carrying blood to our cells constrict and the oxygen in our blood is unable to reach the cells in sufficient quantity. This includes the carotid arteries which carry blood (and oxygen) to the brain.
• The lack of sufficient oxygen going to the cells of the brain can turn on our sympathetic nervous system, our “fight or flight” response, and make us tense, anxious, irritable, and depressed. So remember, when possible, to breathe through your nose.
• Also breathing through the mouth tends to inflate only the upper lobes of the lungs, which are connected to sympathetic nerve fibers, the branch of the nervous system that activates the flight-or-flight fear response. … When you switch to nose breathing, you inflate the entire lung, including the lower lobes, which are connected to the parasympathetic branch of the nervous system, the branch that calms the body, slows the heart rate, relaxes, and soothes. Through proper nose breathing, you employ both branches of the nervous system.
• Isn’t it amazing how our bodies were designed perfectly with one system affecting the other.
  For more on nasal breathing and relaxation click here.