Swallowing during sleep is a common occurrence that most people do not notice or pay attention to. However, understanding your nighttime swallowing patterns can provide insight into your health and sleep quality. In this article, we will explore the average swallowing frequency during sleep, factors that affect it, and whether excessive nighttime swallowing could indicate an underlying condition.
The Basics of Swallowing
Swallowing, also known as deglutition, is an intricate process that allows us to move food and liquid from our mouths down to our stomachs. It is an automatic reflex controlled by the swallowing center in the brainstem. When we swallow, a series of muscle contractions push the food or liquid into the pharynx and then the esophagus, which delivers it into the stomach.
Normal swallowing requires the precise coordination of over 50 pairs of muscles in the face, mouth, tongue, throat, and esophagus. The process begins when the tongue pushes the food or liquid to the back of the mouth. The soft palate then rises to close off the nasal passages, preventing food from entering the nose. Next, the larynx moves upward and the epiglottis folds backward to cover the trachea or windpipe, blocking off the airway. At the same time, the upper esophageal sphincter – a ring of muscle at the top of the esophagus – relaxes to allow the passage of food. Finally, peristalsis, a series of wave-like muscle contractions, carries the food down the esophagus and into the stomach.
We swallow hundreds of times per day when we are awake and eating. But what about when we are asleep?
Do You Swallow in Your Sleep?
Yes, swallowing does occur during sleep. In fact, nighttime swallowing is considered normal and necessary.
Several studies using videofluoroscopy – a technique that captures moving x-ray images of the swallowing process – have confirmed that swallowing happens periodically throughout all stages of sleep. Researchers observing sleepers in labs found that spontaneous swallows occurred around once every hour.
However, the swallowing mechanism works slightly differently when we are sleeping compared to when we are awake.
Key Differences in Nighttime Swallowing
- The swallowing reflex seems to be blunted. Swallows occur less frequently and the muscles have to work harder to generate enough pressure.
- The epiglottis may not cover the airway as efficiently before a swallow, increasing the risk of food or liquid entering the windpipe.
- Swallowing during sleep takes longer to complete.
- There are longer pauses between spontaneous nighttime swallows.
Despite these differences, nighttime swallows are still normally coordinated and safe. If swallowing patterns are severely disrupted during sleep, it can lead to issues like choking or aspiration pneumonia.
Why Do We Swallow in Our Sleep?
There are a few key reasons we continue to swallow while sleeping:
To Clear Saliva
Saliva pools at the back of the throat when we sleep. Swallowing works to regularly clear this saliva and prevent choking or drooling.
To Clear Small Amounts of Gastroesophageal Reflux
When stomach acid leaks up into the esophagus, especially after large meals, nighttime swallowing helps to clear this refluxed liquid and reduce irritation of the esophageal lining.
To Maintain Upper Airway Patency
Swallowing helps keep the upper airway open during sleep by stimulating muscle contraction. This may prevent snoring and sleep apnea caused by airway collapse.
How Many Times Do People Swallow During Sleep?
On average, most studies show that healthy adults spontaneously swallow around 1-3 times per hour while sleeping. This amounts to anywhere from 5 to 30 swallows during a normal 8 hour sleep period.
However, there can be significant individual variation in nighttime swallowing frequency based on factors like:
Age
Infants tend to swallow more frequently during sleep, around 3-5 times per hour. Swallowing rates decrease in adulthood and may further decline in older age.
Sleep State
Swallowing appears to happen more often during lighter sleep stages like NREM1 and REM sleep, compared to deep slow-wave sleep.
Body Position
Lying down increases swallowing frequency compared to sitting or standing upright.
Medications
Certain sedatives, antidepressants, and muscle relaxants can suppress the swallowing reflex.
Medical Conditions
Neurological disorders, muscular diseases, stroke, and obstructive sleep apnea may alter normal swallow patterns during sleep.
Gastroesophageal Reflux Disease (GERD)
Frequent nighttime reflux can stimulate more frequent swallowing.
Hypersalivation
Excess saliva production while sleeping often increases spontaneous swallowing.
Pregnancy
Hormonal changes and increased intra-abdominal pressure can promote reflux and additional swallowing in pregnancy.
Excessive Nighttime Swallowing
Most people swallow 1-3 times per hour during sleep without issues. But excessive nighttime swallowing, known as primary sleep-related swallowing disorder, may affect around 1% of adults.
Frequent bouts of swallowing can significantly impact sleep quality and health. People who swallow more than 5 times per hour during sleep tend to experience:
- Frequent awakenings and arousal from sleep
- Severe daytime fatigue and sleepiness
- Chronic insomnia
- Morning hoarseness
- Aspiration pneumonia
- Weight loss or malnutrition from avoiding food and drink before bed
Causes of increased swallowing at night include:
Gastroesophageal Reflux Disease (GERD)
Frequent acid reflux episodes can stimulate repetitive swallowing.
Laryngopharyngeal Reflux Disease (LPRD)
Reflux of stomach contents into the larynx and pharynx can trigger swallowing.
Esophageal Motility Disorders
Poor function of esophageal muscles may allow increased backward flow and regurgitation while lying down.
Delayed Gastric Emptying
Slowed emptying of the stomach can worsen reflux after meals.
Hiatal Hernia
Prolapse of part of the stomach through the diaphragm can promote acid reflux.
Pregnancy
Hormonal and physical changes increase reflux and swallowing needs.
Obesity
Extra weight presses on the abdomen and frequently causes reflux issues.
Respiratory Disorders
Conditions like sleep apnea that block airflow can impair swallowing coordination.
Neurological Disease
Disorders affecting the brainstem swallowing control center may increase repetitive swallowing.
Tests and Diagnosis
To identify an underlying cause of excessive nighttime swallowing, doctors may recommend:
- Endoscopy – A small camera on a flexible tube passed down the throat to examine esophageal inflammation, ulcers, and strictures.
- Esophageal Manometry – A pressure sensor tube measures muscle contractions during swallows to detect motility disorders.
- 24-Hour pH Monitoring – A probe placed in the esophagus records acid levels to identify reflux.
- Barium Swallow X-Ray – Swallowing barium shows the swallowing mechanism and any aspiration into the lungs.
- Sleep Endoscopy – Observing the airway under sedation determines causes of awakenings like snoring or apnea.
Treatment Options
Treatment depends on the specific reason for excessive nighttime swallowing. Possible options may include:
- Diet Modifications – Avoiding triggers like caffeine, alcohol, large meals, and certain foods before bed.
- Sleep Positioning – Elevating the head in bed and sleeping on the left side can reduce reflux.
- Medications – Such as antacids, histamine blockers, proton pump inhibitors to reduce stomach acid production.
- Surgery – Fundoplication surgery can strengthen the lower esophageal sphincter to prevent reflux and the need to swallow frequently.
- Oral Appliances – Devices like mandibular advancement splints may improve airflow and reduce sleep-disordered breathing triggering arousals and swallows.
- Swallowing Therapy – Exercises performed with a speech-language pathologist aim to strengthen swallowing coordination and reduce aspiration risk.
The most effective approach depends on the diagnosed cause of problematic nighttime swallowing. An otolaryngologist or gastroenterologist can help identify appropriate treatment options tailored to the individual.
When to See a Doctor
Occasional nighttime swallowing is normal. But if you experience:
- Frequent awakenings due to swallowing
- Choking or coughing episodes at night
- Wet, gurgly breathing sounds during sleep
- Aspiration pneumonia
- Weight loss from fear of eating/drinking before bed
- Extreme daytime fatigue and sleepiness
It is important to discuss your symptoms with your doctor. Uncontrolled frequent swallowing can severely impact sleep and cause malnutrition over time. A sleep study or swallow evaluation can help diagnose any underlying disorders causing excessive nighttime swallowing.
Conclusion
Swallowing up to 3 times per hour during sleep is considered normal and necessary. It helps clear saliva, small amounts of reflux, and maintain airway patency. However, chronic excessive nighttime swallowing can indicate issues like GERD, sleep apnea, and neurological or motility disorders. Treatment depends on the cause but may include diet changes, sleep positioning, medications, oral appliances, surgery, and swallowing therapy. See your doctor right away if you experience frequent swallowing disturbances disrupting sleep or health.
