Sleep apnea is a condition where your breathing repeatedly stops and restarts while you sleep. These pauses can happen dozens or even hundreds of times per night, each one lasting seconds to over a minute. An estimated 936 million adults worldwide between the ages of 30 and 69 have some form of sleep apnea, and up to 80% of moderate-to-severe cases remain undiagnosed.
Types of Sleep Apnea
The most common form is obstructive sleep apnea (OSA), which accounts for the majority of cases. It happens when the muscles in the back of your throat relax too much during sleep, causing the airway to physically collapse and block airflow to your lungs. Think of it like a flexible tube being pinched shut.
Central sleep apnea is far less common. The airway stays open, but your brain temporarily stops sending the signal to breathe. Instead of a physical blockage, it’s a communication failure between your brain and the muscles that control breathing. Some people develop a mix of both types, called complex or mixed sleep apnea, which sometimes emerges during treatment for obstructive sleep apnea.
Symptoms You Might Notice
The hallmark nighttime signs are loud snoring (especially common in men), breathing that starts and stops, and gasping for air. The tricky part is that you’re asleep when these happen, so a bed partner is often the first to notice. Other nighttime symptoms include waking up frequently to urinate and insomnia, which is more commonly reported by women.
During the day, the effects are easier to spot: persistent sleepiness and fatigue, morning headaches, dry mouth when you wake up, trouble focusing or learning new things, and reduced sex drive. Women tend to report fatigue and headaches more often than classic loud snoring, which is one reason sleep apnea in women frequently goes unrecognized.
How It Differs in Children
Children with sleep apnea don’t typically present with daytime sleepiness the way adults do. Instead, the most visible signs are behavioral: acting hyper, impulsive, or aggressive, and having difficulty paying attention. These symptoms overlap significantly with ADHD, which can lead to misdiagnosis. Bedwetting that starts again after a long dry period is another red flag. The most common physical cause in kids is enlarged tonsils and adenoids blocking the airway.
What Puts You at Risk
Excess weight is the strongest modifiable risk factor. Fat deposits around the upper airway narrow the space available for airflow. A neck circumference greater than 17 inches in men is a common physical marker, as it often reflects fatty tissue surrounding the airway. Beyond weight, the structure of your jaw, the size of your tongue, and your age all play a role. Sleep apnea prevalence in adults ranges from 9% to 38% depending on how strictly it’s defined, with rates climbing as populations age and obesity rates rise.
Why It’s More Than Just Bad Sleep
Every time your breathing stops, oxygen levels in your blood drop. This is called intermittent hypoxia, and it triggers a cascade of problems throughout your body. Your nervous system kicks into a stress response, releasing a surge of adrenaline-like chemicals that raise your blood pressure. Studies in healthy volunteers exposed to just 14 nights of intermittent low oxygen showed elevated daytime blood pressure, which took five days to normalize after the exposure ended. In people with untreated sleep apnea, this stress response fires repeatedly every single night, sometimes for years.
The physical strain goes beyond blood pressure. Each time you try to breathe against a closed airway, you generate large swings in pressure inside your chest. These swings overload the right side of your heart and stretch the left atrium, creating the conditions for an irregular heart rhythm called atrial fibrillation. Over time, untreated sleep apnea is significantly associated with coronary artery disease, heart failure, stroke, and type 2 diabetes.
How Sleep Apnea Is Diagnosed
Diagnosis starts with measuring how many times your breathing pauses or becomes dangerously shallow per hour of sleep. This number is called the apnea-hypopnea index, or AHI. The severity scale breaks down like this:
- Mild: 5 to fewer than 15 events per hour
- Moderate: 15 to fewer than 30 events per hour
- Severe: 30 or more events per hour
The gold standard test is an overnight sleep study, called polysomnography, conducted in a sleep lab. Sensors track your brain waves, eye movements, heart rhythm, breathing effort, oxygen levels, and body position throughout the night. It’s the only test that can diagnose all types of sleep disorders, including central sleep apnea.
If your doctor strongly suspects moderate-to-severe obstructive sleep apnea and you don’t have other complicating conditions, a home sleep test may be an option. These portable devices are simpler, measuring fewer signals, and you wear them in your own bed. They work well for straightforward cases but can’t detect central sleep apnea or other sleep disorders. Home tests are also sometimes used to monitor how well a treatment is working after the initial diagnosis.
Treatment Options
The first-line treatment for obstructive sleep apnea is a CPAP machine, which delivers a steady stream of air pressure through a mask to keep your airway open while you sleep. It works well when used consistently, but the mask, noise, and sensation of pressurized air can take getting used to. Many people need a few weeks of adjustment and sometimes a few different mask styles before finding a comfortable setup.
For people who need different pressure levels when breathing in versus out, a BiPAP machine offers two preset pressure settings. This can feel more natural and is sometimes better tolerated. A third option, adaptive servo-ventilation (ASV), goes further by continuously monitoring your breathing pattern and adjusting air pressure in real time. ASV is typically reserved for central sleep apnea, complex sleep apnea, or cases where CPAP and BiPAP haven’t worked.
Beyond Breathing Machines
Oral appliances, custom-fitted by a dentist, work by repositioning the lower jaw forward to keep the airway open. They’re generally used for mild to moderate cases or for people who can’t tolerate CPAP.
For people with moderate-to-severe obstructive sleep apnea who have tried and failed CPAP, an implantable nerve stimulator is an option. A small device placed under the skin of the chest stimulates the nerve that controls tongue movement, keeping the airway open during sleep. Candidates must be 18 or older, have a BMI under 32, and not have significant central apnea events. A sleep endoscopy is done first to confirm the pattern of airway collapse is one the device can address.
Weight loss remains one of the most effective long-term strategies. Even a moderate reduction in body weight can significantly reduce the number of breathing events per hour and, in some cases, resolve mild sleep apnea entirely. For children, the most common treatment is surgical removal of enlarged tonsils and adenoids, which eliminates the physical obstruction in the majority of pediatric cases.