Causes Of Sleeping With Mouth Open

Getting a sound sleep during the night is essential to one’s physical and mental well-being. But, breathing with your mouth open could hamper your normal sleep routine and also cause various other complications. It usually occurs when the nasal air passages are obstructed, preventing the free flow of air to and from the lungs.

Breathing through your mouth while asleep is common when one has a nasal congestion, but doing the same when your air passages aren’t clogged could indicate an underlying health condition. It is necessary that you consult your doctor since any of the below reasons could be the cause for you to be sleeping with your mouth open.


Causes Of Sleeping With Mouth Open

1. Deviated Septum

Deviated Septum may cause to sleep with open mouth

The two nostrils are divided evenly by a cartilage called septum. However, in some people, the septum is inclined at a greater angle on one side, leading to one nostril being larger than the other. Research indicates that at least 80% of the population has uneven nostrils to some degree. But, if the deviation is deeper, it could block the nasal passages, making your body switch its channel of oxygen from nose to mouth. This involuntarily causes you to sleep with your mouth open.


2. Obstructive Sleep Apnea

poeple with obstructive sleep apnea sleep with mouth open

Obstructive Sleep Apnea (OSA) is a condition characterised by shallow breathing or even lack of breathing for a brief period, involuntarily, during sleep. It occurs as a result of a blockage in the upper airways, causing your lungs and diaphragm to work harder to get the necessary oxygen. During such an episode, one breathes through the mouth while asleep.1


Normal breathing usually resumes within a few seconds with a body jerk, snort, or a loud gasp. Though you might be unaware of these quick events while asleep, it might lead to severe complications like heart disease, hypertension, stroke, and diabetes.

3. Enlarged Tonsils

enlarged tonsils might cause sleeping with mouth open


Tonsils are the lymph nodes present at the back of the throat and are a part of the immune system. An infection of the tonsils (tonsillitis) leads to their enlargement which results in the blockage of the air passage. People with chronic tonsillitis gradually develop obstructive sleep apnea which, as mentioned before, deters the easy passage of air. This is yet another reason for sleeping with mouth open.

4. Inflamed Adenoids

inflamed adenoids causes sleeping with open mouth


Like tonsils, adenoids are also a part of the immune system fighting infections, which are prominently present during the childhood. They tend to shrink considerably as we age. Adenoids enlarge due to an infection which blocks the airways. In severe cases, it also causes obstructive sleep apnea.

5. Nasal Polyps

nasal polyps might cause people sleep with mouth open


Nasal polyps are benign (noncancerous) growths of the lining tissue (mucosa) in the nose. The symptoms are similar to that of a common cold or a congestion that doesn’t subside even after taking over the counter medication. However, when untreated, they grow significantly leading to an obstruction of the nasal passages. This ultimately leads to breathing through the mouth.

Apart from these, the shape of your nose and jaw could also impact your channel of breathing. In very rare cases, a tumor could be the reason why you are breathing through your mouth.


A quick diagnosis is recommended if you or your loved one is sleeping with the mouth open, as it might lead to further complications. Some of them are a throat infection, ear infection, gingivitis (infection of the gums), bad breath, and tooth cavities. In children, it might lead to issues like poor growth, narrow face, and poor posture. Lack of concentration and poor academic performance also result due to insufficient sleep.