Many of us wake up to the smell of napalm in the morning, otherwise known as morning breath. Morning breath is a potent form of halitosis, the medical term for bad breath, and isn't always relieved by a cursory swish of mouthwash. Some people rarely develop serious morning breath, but some experts estimate up to 95% of the general population experiences morning halitosis from time to time.
There are a number of root causes for morning breath. One trigger is the amount of food residue and mucus remaining in the mouth overnight. During the day, natural saliva and ingested liquids generally keep food and mucus moving past the tongue and upper throat. At night, however, the salivary glands produce very little saliva and the mouth can become very dry. Certain anaerobic bacteria which live in the oxygen-free crevices of the tongue and throat are no longer held at bay, so they begin to feed on the food and mucus. Their waste products are primarily sulfur-based, which creates a very pungent smell when exposed to air.
When many people reach a deep sleep stage, their tongues often relax and naturally fall towards the back of the throat. This action prevents substantial levels of oxygen to reach the back of the mouth during overnight hours. The normal aerobic bacteria which protect the mouth cannot function without oxygen, so essentially the anaerobic bacteria can continue to eat all night without interference. This means a noticeable amount of sulfurous waste can be generated in an eight to ten hour period. Morning breath is the result of an all-night eating binge by sulfur-emitting bacteria.
Even if a person studiously brushes both his or her tongue and teeth and finishes with a strong mouthwash rinse, the body still produces a natural food source for bacteria called mucus. Scraping the tongue and brushing thoroughly at bedtime, however, can help to reduce the severity and duration of morning breath.
There are a number of oral hygiene products available which address the symptoms of morning breath, but most only rinse away the surface waste products or kill a small number of bacteria. The best treatment for morning breath may be breathing air and drinking water. Eventually the aerobic bacteria population should increase and drive the anaerobic bacteria back into their hiding places in the mouth and throat.