Many of us have experienced this problem at one point or another during our lives: awakening with that nasty sensation of uncomfortable dryness in the morning. Your saliva–or what’s left of it–feels like paste; there’s that funky, faintly cheesy taste in your mouth that you’re sure doesn’t smell good either.
Dry mouth, or xerostomia, can be a particular problem at night. Saliva is necessary to protect and lubricate the structures of the mouth and throat, as well as their fragile mucosal linings, from friction, foreign particles (food), and virulent organisms (viruses and bateria). While sleeping, your salivary glands naturally and normally slow down production of this saliva, and so in some respects it may be natural to awaken feeling like your mouth is a little dry. In some, however, dry mouth at night or in the early morning can be a substantial problem and a source of genuine discomfort; the words “Sahara desert” and “bone dry” are often used by my patients, for example, to describe this unpleasant sensation.
There are a number of potential causes for substantial dry mouth. Aging into your 70’s and 80’s, for example, often further slows down saliva production. Dehydration and metabolic imbalances may cause dry mouth as well. Certain medical disorders, such as Sjögren’s Syndrome and lupus, often are associated with dry mouth, as are a variety of different medications, such as antihistamines, certain blood pressure lowering drugs, diuretics (“water pills”), and anti-depressants.
Another important thing to think about is whether your mouth is open while you are sleeping. For many open-mouth breathers, the lower jaw (mandible) may naturally fall a little due to a combination of gravitational effects and jaw muscle slackening while asleep; some may be predisposed to this tendency more than others, and other factors–like body weight, neck circumference, and body position(s) of sleep–may influence mouth opening during sleep as well. However, it’s important to know if there are other problems that may cause chronic mouth opening during sleep as well, in particular things that can cause nasal congestion or other decreases in airflow through the nasal passages–such as chronic allergies, a substantially deviated nasal septum, and sinus infections. It stands to reason that if you can’t breathe properly through your nose, your mouth may be more likely to open during sleep to maintain proper airflow.
Another problem is that obstructive sleep apnea (a breathing disorder in which the airway collapses during sleep) is commonly associated with open-mouth breathing and, hence, mouth dryness and throat and oral irritation at night or in the morning. People with sleep apnea often snore loudly. Now keep in mind that you can snore with your mouth or closed (try simulating snoring with your mouth open and then with your mouth closed; you’ll see what I mean), but the snoring is generally louder with your mouth open. As a result, sleep apnea can be more noticeable to a bed partner, because the snoring is more bothersome and the loudness of the snoring provides a greater sound contrast when you sound like you stop your breathing during sleep (which is what the sleep apnea does, due to blockage of the upper airway). So as a clinician, I actually look at the open-mouth breathing as, in a paradoxical way, a good thing: it makes the sleep apnea more bothersome to both the patient and the bed partner, thus making it more likely to be brought to the attention of a physician (studies demonstrate that in the United States, about 85% of sleep apnea cases are still not yet diagnosed!).
So here are my first take-home points of 2014! I recommend that you consider these possibilities if you frequently awaken with xerostomia. Bring symptoms consistent with reduced airflow through your nose to the attention of your doctor when you speak with him/her about the dry mouth. If your oral symptoms are accompanied by a history of substantial snoring, and certainly is someone is telling you that you sound like you’re also stopping your breathing during your sleep, I strongly urge you to discuss these important issues with your doctor and consider an evaluation by a person like me, a physician who specializes in sleep medicine.
Have a great week, everyone!