ELi5: Why is it often recommended to breathe in through your nose and out through your mouth?
In: Biology
The nose and sinuses are specifically evolved to increase air temperature also to moisten and filter the air before it enters the lungs. This is important for the health and comfort of your lungs. That explains the breathing in part. But why out your mouth?
Well, because the sinuses are gory to trap all the filter stuff… also because they are narrow, breathing out in a sudden relaxation of the diaphragm results in blowing that mucus out and making your nose runny. It also forces pressure on the lungs by backing up the air slightly at the nose and increased pressure from a relaxed diaphragm. (Your breathe muscle).
So, by exhaling thru the mouth you can let air quickly leave the lungs without runny noses or increased pressure. This helps the body relax without instinct reflexes of increased lung pressure.
In thru the filter straw, out thru a drain.
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