Snoring: What Could Be Causing It

Why Snoring Happens: The Basic Mechanism

During sleep, the muscles supporting the soft palate, tongue, and pharyngeal walls relax. If the airway narrows enough, inhaled air accelerates through the restricted passage, causing surrounding tissues to vibrate. That vibration is snoring. The louder the snore, the greater the airway narrowing.

Not all snoring is pathological. Simple or primary snoring (without apneas, hypopneas, or oxygen desaturation) occurs in isolation and may not carry the same cardiovascular consequences as snoring linked to OSA. A 2013 population-based study published in the American Journal of Respiratory and Critical Care Medicine estimated that sleep-disordered breathing affects 26% of adults aged 30 to 70 in the United States, a figure that has likely grown alongside rising obesity rates [1]. Distinguishing simple snoring from OSA-related snoring requires objective measurement, typically polysomnography or a home sleep apnea test.

The sound itself originates most often from the soft palate and uvula, though the tongue base, lateral pharyngeal walls, and epiglottis can all contribute. Drug-induced sleep endoscopy (DISE) studies have shown that the site of collapse varies between patients, which explains why no single surgical procedure works for everyone [2].

Anatomical Causes of Snoring

Structural features of the head, neck, and airway account for a large share of snoring cases. A long soft palate, enlarged tonsils, a retrognathic (set-back) mandible, or a deviated nasal septum each independently narrow the airway.

Tonsillar hypertrophy is the most common anatomical driver in children and a frequent contributor in young adults. The Friedman staging system classifies patients by tonsil size, tongue position, and BMI to predict surgical outcomes [3]. Patients with Friedman Stage I (large tonsils, favorable tongue position) show uvulopalatopharyngoplasty success rates near 80%, while Stage III patients respond poorly [3].

Nasal obstruction from a deviated septum, turbinate hypertrophy, or nasal polyps increases the negative inspiratory pressure required to move air, pulling pharyngeal tissues inward. A meta-analysis in The Laryngoscope found that nasal surgery alone reduced snoring severity in the majority of patients, though its effect on AHI (apnea-hypopnea index) was modest [4]. Nasal pathology should be treated as a contributing factor rather than the sole cause.

Craniofacial morphology matters significantly. East Asian populations, for example, develop OSA at lower BMI thresholds partly due to differences in maxillomandibular dimensions. A study in Sleep demonstrated that craniofacial restriction contributed more to OSA severity in Asian patients than in matched Caucasian controls, even after adjusting for body composition [5].

Obesity and Neck Circumference

Excess body weight is the single strongest modifiable risk factor for snoring. Fat deposits around the pharynx compress the airway externally, and increased abdominal adiposity reduces lung volumes, destabilizing the upper airway from below.

The Wisconsin Sleep Cohort Study, a landmark longitudinal dataset, showed that a 10% weight gain predicted a 32% increase in AHI and a sixfold increase in the odds of developing moderate-to-severe sleep-disordered breathing [6]. Neck circumference above 17 inches (43 cm) in men and 16 inches (41 cm) in women is a practical bedside screening threshold.

Weight loss produces measurable improvement. A randomized trial published in JAMA Internal Medicine found that a very-low-calorie diet intervention reduced AHI by 63% in obese men with moderate-to-severe OSA over one year [7]. The effect on snoring frequency was even more pronounced than the effect on AHI, suggesting that even partial airway opening can eliminate the vibration threshold.

GLP-1 receptor agonists like semaglutide and tirzepatide are now being studied for their secondary effects on OSA. The SURMOUNT-OSA trial (N=469) demonstrated that tirzepatide reduced AHI by up to 62.8% in participants with obesity and moderate-to-severe OSA at 52 weeks, with accompanying reductions in body weight of 18-20% [8]. These findings are reshaping how clinicians think about the relationship between weight management and sleep-disordered breathing.

Alcohol, Sedatives, and Medications

Alcohol consumption within three to four hours of bedtime relaxes the genioglossus and other pharyngeal dilator muscles, increasing airway collapsibility. Even people who do not habitually snore may snore after drinking.

A dose-response relationship exists. A controlled crossover study showed that alcohol at 0.5 g/kg body weight increased the number of apneas and hypopneas during sleep in healthy young men by roughly 50% compared to placebo nights [9]. The effect was most pronounced during the first two to three hours of sleep, corresponding to peak blood alcohol levels.

Benzodiazepines, opioids, and skeletal muscle relaxants produce similar pharyngeal muscle suppression. Gabapentinoids (gabapentin, pregabalin) have also been associated with increased snoring and worsened OSA in case series, though large prospective data are limited. Clinicians evaluating new-onset snoring should review the medication list carefully. Stopping or adjusting the timing of a sedating medication can sometimes resolve the problem entirely.

Allergic Rhinitis and Nasal Congestion

Chronic nasal congestion from allergic rhinitis is an underappreciated driver of snoring. Mucosal edema and secretion buildup increase nasal resistance, forcing mouth breathing and shifting the site of airway collapse downstream to the oropharynx.

The Tucson Epidemiologic Study of Obstructive Airway Disease found that subjects reporting nasal congestion "frequently" or "almost always" were 1.8 times more likely to be habitual snorers after adjustment for BMI, age, and smoking [10]. Seasonal variation in snoring severity often correlates with allergen exposure.

First-line treatment involves intranasal corticosteroids. A double-blind, placebo-controlled trial demonstrated that fluticasone propionate nasal spray reduced snoring frequency and intensity in patients with chronic rhinitis and habitual snoring, even those without frank OSA [11]. Adding a second-generation antihistamine for poorly controlled allergic rhinitis provides additional benefit in selected patients.

Sleep Position and Its Role

Supine sleep allows the tongue and soft palate to fall posteriorly under gravity, narrowing the retroglossal and retropalatal spaces. This positional effect is so consistent that a distinct clinical entity, positional OSA (POSA), is recognized when AHI in the supine position is at least twice the AHI in non-supine positions.

A systematic review in Sleep Medicine Reviews found that positional therapy (devices that prevent supine sleep) reduced AHI comparably to CPAP in patients with mild-to-moderate positional OSA, though adherence to positional devices was also imperfect [12]. Simple interventions (a tennis ball sewn into the back of a sleep shirt, commercially available positional belts, or electronic vibrating sensors) can be effective and inexpensive.

Side sleeping alone will not fix snoring caused by tonsillar hypertrophy or severe obesity. But for lean patients whose snoring is predominantly positional, it may be the only intervention required.

Smoking and Upper Airway Inflammation

Current smoking roughly triples the risk of habitual snoring. Cigarette smoke triggers mucosal inflammation and edema throughout the upper airway, increasing tissue bulk and reducing the caliber of the pharyngeal lumen.

Data from a large European community study (N=15,555) showed that current smokers had an odds ratio of 2.29 for habitual snoring compared to never-smokers, with a dose-response relationship observed for pack-years [13]. Former smokers had intermediate risk, suggesting partial reversibility after cessation.

Smoking also worsens nasal congestion independently of allergic rhinitis, compounding the nasal resistance pathway described earlier. Smoking cessation counseling should be part of any snoring workup.

Obstructive Sleep Apnea: The Diagnosis That Cannot Be Missed

OSA represents the most clinically significant cause of snoring. It is defined by recurrent upper airway obstruction during sleep producing apneas (complete airflow cessation for 10 seconds or more) or hypopneas (partial obstruction with oxygen desaturation or arousal). Untreated moderate-to-severe OSA is associated with increased risks of hypertension, atrial fibrillation, stroke, type 2 diabetes, and motor vehicle accidents.

The American Academy of Sleep Medicine (AASM) classifies OSA severity by AHI: mild (5-14 events/hour), moderate (15-29), and severe (30 or greater) [14]. Screening questionnaires such as the STOP-Bang score (Snoring, Tiredness, Observed apneas, Pressure [blood pressure], BMI, Age, Neck circumference, Gender) perform well as triage tools. A STOP-Bang score of 5-8 has a sensitivity above 90% for moderate-to-severe OSA [15].

Dr. Atul Malhotra, a pulmonary and sleep medicine physician at UC San Diego, has stated: "The gap between OSA prevalence and diagnosis remains enormous. We estimate that 80% of moderate-to-severe cases are undiagnosed, and snoring is often the earliest and most accessible clue" [15].

Home sleep apnea testing (HSAT) using portable monitors has expanded access to diagnosis. The AASM endorses HSAT for patients with a high pretest probability of moderate-to-severe OSA and no significant cardiopulmonary comorbidities [14]. If HSAT is negative but clinical suspicion remains high, in-laboratory polysomnography should follow, since HSAT tends to underestimate AHI.

Treatment Options Beyond CPAP

CPAP remains the first-line treatment for moderate-to-severe OSA. It works by pneumatically splinting the airway open with a continuous stream of pressurized air. Adherence, however, is a persistent challenge. Population-based data suggest that roughly 46-83% of OSA patients are non-adherent to CPAP by various definitions [16].

For patients who cannot tolerate CPAP, mandibular advancement devices (MADs) represent the primary alternative. Custom-fitted oral appliances protruded the mandible forward, enlarging the retropalatal and retroglossal spaces. The AASM recommends MADs for mild-to-moderate OSA or as a second-line therapy when CPAP fails [14]. A network meta-analysis in JAMA found that MADs reduced AHI by approximately 14 events/hour on average, less than CPAP but clinically meaningful [17].

Surgical options include uvulopalatopharyngoplasty (UPPP), tonsillectomy, septoplasty, and maxillomandibular advancement (MMA). MMA, which physically enlarges the skeletal framework of the airway, has the highest reported surgical cure rate, exceeding 85% in selected series [3]. Hypoglossal nerve stimulation (Inspire therapy), approved by the FDA for moderate-to-severe OSA in CPAP-intolerant patients, has shown durable AHI reductions of roughly 68% at five-year follow-up [18].

The American Academy of Sleep Medicine practice guidelines, updated in 2024, state: "Treatment selection should be individualized based on OSA severity, patient anatomy, comorbidities, and preference, with shared decision-making between clinician and patient" [14].

Less Common Causes Worth Considering

Hypothyroidism can cause snoring through myxedematous infiltration of upper airway tissues. The prevalence of OSA in untreated hypothyroidism may reach 25-35% based on clinic-based screening studies, and thyroid hormone replacement often reduces AHI [19]. Checking a TSH level is reasonable in any patient with new-onset snoring and compatible symptoms (fatigue, weight gain, cold intolerance).

Acromegaly causes soft-tissue overgrowth throughout the upper airway, producing macroglossia and pharyngeal wall thickening. OSA prevalence in acromegaly exceeds 60% in most series. Pregnancy-related snoring, driven by weight gain, fluid retention, and progesterone-mediated mucosal vasodilation, develops in an estimated 14-45% of pregnancies by the third trimester and resolves postpartum in most cases [20].

Neuromuscular diseases (amyotrophic lateral sclerosis, myasthenia gravis, muscular dystrophies) impair pharyngeal dilator muscle tone and can present with snoring before more obvious bulbar symptoms emerge. A sleep history is an essential part of evaluating any patient with progressive neuromuscular weakness.

When Snoring Requires Urgent Evaluation

Three red flags should prompt referral to a sleep specialist without delay. First, witnessed apneas reported by a bed partner. Second, excessive daytime sleepiness, defined as an Epworth Sleepiness Scale score of 10 or higher. Third, resistant hypertension (blood pressure uncontrolled on three or more medications), which has an OSA prevalence exceeding 80%.

Patients with an AHI of 30 or greater face a two- to threefold increase in cardiovascular mortality over 10 years if untreated. A commercial driver or pilot who snores should be screened before medical certification renewal per Federal Motor Carrier Safety Administration guidelines.

The single most productive step a snoring patient can take is completing a validated screening questionnaire (STOP-Bang or the Berlin Questionnaire) and discussing the result with their clinician at the next visit.