Obstructive Sleep Apnea (OSA): Causes, Symptoms, and Treatment

Obstructive sleep apnea (OSA) is a condition where your airway repeatedly closes during sleep. Each closure stops your breathing for 10 seconds or more. This happens dozens or even hundreds of times per night. About 936 million adults worldwide have OSA, but 80–90% of cases go undiagnosed.

What Happens During an Apnea Episode?

When you fall asleep, your muscles relax. In OSA, the muscles in your throat relax too much. Your tongue and soft tissues fall backward. They block your airway partially or completely.

Your brain senses the drop in oxygen and briefly wakes you up — just enough to reopen the airway. You gasp, take a breath, and fall back asleep. Most people don't remember these arousals. But they fragment your sleep hundreds of times per night.

This cycle of collapse, arousal, and recovery is what makes OSA so damaging. Your body never gets the deep, restorative sleep it needs.

What Causes OSA?

• Excess weight: Fat deposits around the upper airway narrow the breathing passage. This is the biggest risk factor.
• Anatomy: A thick neck, large tonsils, long uvula, or recessed jaw reduce airway space.
• Age: Muscle tone decreases with age. OSA is most common after age 50.
• Male sex: Men are twice as likely to develop OSA as premenopausal women.
• Family history: Genetics affect jaw shape and airway size.
• Alcohol and sedatives: They relax throat muscles more than normal sleep does.
• Smoking: Increases inflammation and fluid retention in the airway.
• Nasal congestion: Chronic stuffiness forces mouth breathing, worsening airway collapse.

Symptoms of OSA

Nighttime Symptoms

• Loud, chronic snoring (often reported by a partner)
• Gasping, choking, or snorting during sleep
• Witnessed breathing pauses
• Restless sleep and frequent awakenings
• Dry mouth or sore throat in the morning
• Night sweats
• Frequent urination at night (nocturia)

Daytime Symptoms

• Excessive daytime sleepiness (even after a full night's sleep)
• Morning headaches
• Difficulty concentrating and memory problems
• Irritability and mood changes
• Decreased sex drive
• Falling asleep during passive activities (watching TV, reading)

OSA Severity: The AHI Scale

Sleep apnea is diagnosed and classified by the Apnea-Hypopnea Index (AHI):

• Normal: AHI under 5
• Mild OSA: AHI 5–14
• Moderate OSA: AHI 15–29
• Severe OSA: AHI 30+

About 425 million adults worldwide have moderate to severe OSA (AHI 15+).

Health Risks of Untreated OSA

OSA is not just about snoring. The repeated oxygen drops and sleep fragmentation take a serious toll on your body:

• High blood pressure: 30–50% of hypertension patients have OSA. 75% of treatment-resistant hypertension is linked to undiagnosed OSA. Read about sleep apnea and blood pressure.
• Heart disease: OSA increases cardiovascular event risk by 76–109%.
• Stroke: Moderate to severe OSA significantly raises stroke risk.
• Type 2 diabetes: OSA worsens insulin resistance.
• Depression and anxiety: Sleep fragmentation affects mood regulation.
• Accidents: Daytime sleepiness causes impaired driving and workplace accidents.

How Is OSA Diagnosed?

Sleep Study Options

• Polysomnography (PSG): Overnight lab study. The gold standard. Measures brain waves, eye movement, muscle tone, heart rate, breathing, and oxygen.
• Home sleep test: A simpler device you wear at home for 1–2 nights. Measures airflow, breathing effort, and oxygen. Good for confirming moderate to severe OSA.

Learn more about how to get tested for sleep apnea.

Treatment Options for OSA

For Mild OSA (AHI 5–14)

• Nasal stent: The Back2Sleep nasal stent keeps the airway open from the inside. CE-certified for mild to moderate OSA. Works from night one.
• Positional therapy: If your AHI is worse on your back, side sleeping can cut events in half. See our guide to positional therapy.
• Weight loss: If overweight, losing 10% of body weight reduces AHI significantly.
• Mouth exercises: Strengthen airway muscles over 3 months of daily practice.

For Moderate OSA (AHI 15–29)

• Oral appliance (MAD): Equally effective as CPAP for moderate OSA. Custom-fitted by a dentist.
• Nasal stent + positional therapy: Combining two treatments often brings AHI into the normal range.
• CPAP: If other treatments don't reduce AHI enough.

For Severe OSA (AHI 30+)

• CPAP: The primary treatment. Most effective when used consistently.
• Surgery: Options include UPPP, palatal implants, or hypoglossal nerve stimulation (Inspire).
• Combination therapy: CPAP + weight loss + positional therapy for maximum reduction.

Compare all options in our treatment comparison guide or explore CPAP alternatives.

OSA vs. Central Sleep Apnea

There are two main types of sleep apnea:

• Obstructive (OSA): The airway physically closes. This is 84% of all sleep apnea cases.
• Central (CSA): The brain fails to signal the breathing muscles. This is less common and usually linked to heart failure or neurological conditions.

Some people have a mix of both, called complex or mixed sleep apnea. Treatment differs between types, so accurate diagnosis is important. Learn more about how to tell sleep apnea from simple snoring.

Living With OSA

OSA is a chronic condition, but it can be managed effectively. Most people notice dramatic improvements in energy, mood, and thinking once they start treatment.

• Stick with your treatment every night, even on weekends and holidays
• Get retested every 1–2 years or if symptoms return
• Monitor your weight — even small gains can worsen AHI
• Avoid alcohol within 3 hours of bedtime
• Tell your doctor about OSA before any surgery (anesthesia is riskier with OSA)

Frequently Asked Questions