Breathing with an open mouth can quickly dry out the airways. Some people breathe with their mouth open when they have a respiratory illness, such as a cold, or due to underlying medical conditions.
Engaging in activities that cause heavy breathing, such as heavy exercise, may also cause a person to breathe with their mouth open.
Additionally, if a person wakes up every morning with a dry mouth, they may be sleeping with their mouth open and inhaling the dry air.
Making a conscious effort to keep the mouth closed and breathe through the nose may help improve saliva flow in some people. Other tips may help with this effort, such as sucking on a sugarless candy.
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