Sleep Apnea Causes & Risk Factors
Obstructive sleep apnea does not have a single cause. It results from a combination of anatomical features, lifestyle factors, medical conditions, and genetics. Understanding your personal risk factors is the first step toward prevention and treatment.
Reviewed by Solve Sleep Apnea Team
Last updated June 2025
What Causes Obstructive Sleep Apnea
During normal sleep, the muscles in your throat relax. In most people, this relaxation does not affect breathing. But in people with obstructive sleep apnea, the airway narrows or collapses completely when these muscles relax — blocking airflow to the lungs.
When airflow stops, blood oxygen levels drop and carbon dioxide rises. Your brain detects this emergency and briefly wakes you — just enough to tighten the throat muscles and reopen the airway. This cycle of collapse, arousal, and recovery can repeat 5 to 100+ times per hour, all night long.
The underlying question is: why does the airway collapse in some people and not others? The answer involves multiple contributing factors.
Anatomical Risk Factors
Your physical anatomy plays a major role in whether your airway is prone to collapse during sleep. These factors are largely determined by genetics and cannot be changed through lifestyle modifications alone.
Narrow airway or crowded throat
Some people are born with a naturally narrow upper airway. This can be due to the size and position of the tongue, soft palate, uvula, tonsils, or adenoids. Even a small amount of relaxation during sleep can be enough to close a narrow airway.
Large neck circumference
A neck circumference greater than 17 inches in men or 16 inches in women is associated with increased OSA risk. Excess tissue around the neck puts pressure on the airway, especially when lying down.
Recessed jaw or chin (retrognathia)
A lower jaw that sits further back than normal positions the tongue closer to the back of the throat, reducing airway space. This is one reason oral appliance therapy — which advances the jaw forward — is so effective.
Enlarged tonsils or adenoids
Particularly common in children, enlarged tonsils and adenoids physically obstruct the airway. In adults, tonsils that were not removed in childhood can still contribute to airway narrowing.
Nasal obstruction
A deviated septum, chronic nasal congestion, or nasal polyps force mouth breathing, which changes the dynamics of airflow and makes airway collapse more likely.
Lifestyle Risk Factors
Unlike anatomical factors, lifestyle risk factors can be modified. Addressing these factors can reduce the severity of sleep apnea and improve treatment outcomes.
Excess weight and obesity
Obesity is the single largest modifiable risk factor for OSA. Approximately 70% of people with sleep apnea are overweight or obese. Fat deposits around the upper airway narrow the breathing passage, and abdominal fat reduces lung volume, making breathing harder. A 10% weight gain increases OSA risk by 6 times.
Alcohol and sedative use
Alcohol and sedating medications (sleeping pills, benzodiazepines, opioids) relax the throat muscles more than normal sleep does. Drinking alcohol within 3-4 hours of bedtime can increase apnea severity by 25-50%. Sedatives can also impair the brain's ability to wake you when breathing stops.
Smoking
Smokers are 2-3 times more likely to have OSA than non-smokers. Smoking causes inflammation and fluid retention in the upper airway, narrowing the breathing passage. Quitting smoking reduces this risk, though it may take months for inflammation to resolve.
Sleeping position
Sleeping on your back (supine) allows gravity to pull the tongue and soft palate backward, narrowing the airway. An estimated 50-60% of OSA patients have position-dependent apnea — their breathing events are significantly worse when supine. Side sleeping can reduce apnea severity in these patients.
Medical Conditions That Increase Risk
Several medical conditions are associated with higher rates of sleep apnea. If you have any of these conditions and experience symptoms of OSA, screening is strongly recommended.
Note: The relationship between these conditions and OSA is often bidirectional. Sleep apnea can worsen diabetes, hypertension, and heart disease — and those conditions can increase sleep apnea severity. Treating OSA often improves the associated condition.
Age and Gender
Sleep apnea risk increases with age, with prevalence rising significantly after age 40. This is partly due to natural loss of muscle tone in the throat and the accumulation of other risk factors over time.
Men are 2-3 times more likely to be diagnosed with OSA than pre-menopausal women. However, after menopause, the gender gap narrows significantly as the protective effects of estrogen and progesterone on airway muscle tone decline. Women with OSA are also significantly underdiagnosed because they often present with different symptoms.
Family history is another important factor. If a parent or sibling has sleep apnea, your risk is 2-4 times higher than the general population. This is partly due to inherited craniofacial features like jaw size and airway dimensions.
Can Sleep Apnea Be Prevented?
You cannot change your anatomy or genetics, but you can reduce your risk and severity by addressing modifiable factors:
Even with lifestyle modifications, many people still need treatment for sleep apnea. The anatomy of the airway is the dominant factor for most patients, and this cannot be changed through lifestyle alone.
Next Steps
If you have multiple risk factors for sleep apnea, getting screened is one of the most important things you can do for your health. A simple home sleep test can determine whether you have OSA and how severe it is. From there, effective treatments like oral appliance therapy can have you sleeping better within weeks.