Sleep Apnea

What sleep apnea is

Sleep apnea is a condition characterized by repeated breathing interruptions during sleep. The most common form — obstructive sleep apnea (OSA) — occurs when the muscles supporting the soft tissue at the back of the throat relax during sleep, allowing the tongue and soft palate to collapse against the airway and block airflow.

Less common forms include central sleep apnea, in which the brain temporarily fails to signal the breathing muscles, and complex (or mixed) sleep apnea, which combines obstructive and central elements. This page focuses on OSA, which accounts for the substantial majority of diagnosed cases.

During an apnea event, breathing stops for at least ten seconds. Blood oxygen levels drop. The brain — sensing the deficit — triggers a brief micro-arousal to restart breathing. The person almost never wakes up enough to remember the event. Then sleep resumes, the cycle repeats, and the body absorbs the cumulative cost of hundreds of these interruptions, every night, for years.

Approximately 30 million American adults are estimated to have OSA. Of those, roughly 80% of moderate-to-severe cases — those most likely to cause meaningful long-term damage — have never been diagnosed or treated.

Symptoms and warning signs

Sleep apnea is unusual among medical conditions because the most reliable warning signs are observed by someone else — typically a bed partner — rather than experienced by the person who has it. The hallmark signs include:

• Loud, habitual snoring observed by a bed partner
• Witnessed pauses in breathing during sleep, often followed by a gasp or choking sound
• Excessive daytime sleepiness, even after a full night in bed
• Morning headaches that resolve within an hour or two of waking
• Difficulty concentrating, short-term memory problems, or unexplained irritability
• Waking up with a dry mouth or sore throat
• Frequent nighttime urination (nocturia) without an obvious cause

Habitual snoring is present in approximately 90% of people with OSA — but not all snoring indicates apnea. The combination that warrants evaluation is loud snoring plus daytime symptoms, particularly excessive sleepiness or any of the other signs above.

If a bed partner has ever observed you stop breathing or gasp during sleep, that observation alone is sufficient reason to pursue a sleep evaluation, regardless of how you feel during the day.

Causes and risk factors

Several factors increase the likelihood of developing OSA. Some are anatomical and largely fixed; others are modifiable through lifestyle changes.

Fixed risk factors

• Age — risk rises substantially after 40
• Family history — first-degree relatives have meaningfully elevated risk
• Anatomical features — enlarged tonsils or adenoids, recessed jaw, large neck circumference (greater than 17 inches in men, greater than 15 inches in women), nasal obstruction
• Male sex — men are diagnosed roughly twice as often as women, though women are significantly underdiagnosed
• Ancestry — higher rates have been observed among Black, Hispanic, and Pacific Islander populations

Modifiable risk factors

• Elevated BMI — each 10% weight gain is associated with a roughly 30% increase in apnea events on average
• Alcohol use, particularly in the hours before sleep
• Smoking
• Sedative or opioid medications that further relax airway muscles
• Sleeping on the back (positional component, present in roughly half of OSA patients)

One of the most underrecognized risk transitions in adult medicine is menopause. Postmenopausal women face approximately three times the OSA risk of premenopausal women — a sharp shift driven by hormonal changes that affect upper airway muscle tone and fat distribution. Women whose snoring or daytime sleepiness emerged or worsened around menopause have a particularly strong indication for evaluation.

How sleep apnea is diagnosed

Sleep apnea cannot be reliably diagnosed by symptoms alone. The diagnostic standard is a sleep study, which directly measures breathing events during sleep. Two formats are commonly used:

In-lab polysomnography (PSG)

The most comprehensive option. The patient spends a single night at a sleep center while sensors simultaneously monitor brain activity, eye movements, heart rate, breathing patterns, blood oxygen levels, and limb movements. PSG is preferred when comorbid conditions are suspected — central sleep apnea, REM behavior disorder, narcolepsy, or complex limb movement disorders all require the broader sensor array.

Home sleep test (HSAT)

A smaller device worn at home that monitors breathing, heart rate, and oxygen levels overnight. Clinically validated for moderate-to-severe OSA in adults without significant comorbidities. More convenient, lower cost, and typically returns results within several days. Most insurance plans cover an HSAT as the appropriate first study for uncomplicated suspected OSA.

The Apnea-Hypopnea Index

The diagnosis is based on the Apnea-Hypopnea Index (AHI) — the average number of breathing events per hour of sleep, including both full apneas (complete pauses) and hypopneas (partial blockages with measurable oxygen drop or arousal).

Treatment is generally indicated for AHI ≥ 5 with daytime symptoms, or AHI ≥ 15 regardless of symptoms. The presence of cardiovascular comorbidities (hypertension, atrial fibrillation, heart failure, prior stroke) lowers the threshold at which treatment is recommended.

Treatment options

OSA is highly treatable. The right approach depends on severity, anatomy, comorbidities, and patient preferences. The options below are presented in approximate order of clinical first-line preference for moderate-to-severe disease.

Continuous Positive Airway Pressure (CPAP)

The gold-standard treatment. A bedside machine delivers gentle, continuous positive air pressure through a mask to keep the upper airway open during sleep. When used consistently for at least four hours per night, CPAP reduces apnea events by 80% or more in most patients and substantially reverses the cardiovascular risk associated with untreated OSA. Modern machines are quiet (under 30 decibels), compact, and travel-friendly.

Mask fit is the single most important variable in CPAP success. Most reported "CPAP failures" are actually mask-fit failures — patients who tried one mask style, found it uncomfortable, and discontinued therapy. Three primary mask categories (nasal pillows, nasal masks, full-face masks) accommodate most anatomy and breathing patterns. Working with an experienced respiratory therapist or sleep specialist to find the right mask is well worth the time.

Oral appliance therapy

A custom-fitted dental device worn during sleep that advances the lower jaw slightly, mechanically holding the upper airway open. Effective for mild-to-moderate OSA, typically reducing apnea events by 50–70%. Best fitted by a dentist with formal sleep-medicine training (the field is called dental sleep medicine). Often the right choice for patients who cannot tolerate CPAP, or who travel frequently and need a more portable option.

Lifestyle modification

Several lifestyle changes can meaningfully reduce OSA severity, sometimes substantially:

• Weight loss — a 10% reduction in body weight can reduce AHI by approximately 25–30% in patients with elevated BMI
• Positional therapy — for patients whose apnea is significantly worse when sleeping on the back, devices and techniques that promote side-sleeping can substantially help
• Alcohol moderation, particularly avoiding alcohol in the three hours before bedtime
• Smoking cessation

Lifestyle changes are usually adjuncts to other treatments rather than standalone solutions for moderate-to-severe disease, but they can shift severity meaningfully and improve outcomes when combined with CPAP or oral appliance therapy.

Surgical and device-based options

Several surgical approaches exist for selected patients who cannot tolerate or do not adequately benefit from CPAP. These include upper airway soft-tissue surgery (UPPP), maxillomandibular advancement (MMA), and implantable hypoglossal nerve stimulators (the Inspire device). Outcomes vary substantially by approach and patient selection. Consultation with a sleep surgeon or sleep specialist with surgical-pathway experience is essential before considering any of these.

What untreated sleep apnea costs

Untreated OSA is associated with significantly elevated risk across multiple organ systems. The relationships are well-established in the clinical literature:

• Cardiovascular disease — 2–3× higher risk of coronary artery disease and heart failure
• Hypertension — approximately 50% of patients with treatment-resistant hypertension have undiagnosed OSA; treating OSA reduces blood pressure
• Stroke — 2–4× higher risk
• Atrial fibrillation — strong bidirectional relationship; OSA treatment reduces post-ablation AFib recurrence
• Type 2 diabetes — OSA reduces insulin sensitivity independently of weight
• Cognitive decline and dementia — accumulating evidence links untreated OSA to elevated dementia risk
• Depression and anxiety — frequently comorbid; treatment of OSA often improves mood
• Motor vehicle accidents — 2–7× higher crash risk due to drowsy driving

These are not theoretical risks. The cumulative effect of years of untreated OSA shows up in real medical outcomes. Crucially, many of these elevated risks are partially or fully reversible with consistent treatment over months to years.

When to see a sleep specialist

A sleep evaluation is appropriate if any of the following apply:

• You snore loudly and habitually, particularly with witnessed breathing pauses
• You experience excessive daytime sleepiness despite adequate sleep time
• You have hypertension, especially if it is difficult to control with medication
• You have atrial fibrillation, type 2 diabetes, heart failure, or have had a stroke
• You have woken up gasping or choking
• You experience morning headaches combined with daytime fatigue
• A bed partner is concerned about your breathing or snoring during sleep

A primary care physician can place a referral, or many sleep centers accept self-referrals directly. A home sleep test can typically be ordered, completed, and reported within one to two weeks. If you've recognized two or more of the above, the next step is straightforward.