Sleep apnoea is a condition where your breathing repeatedly stops and restarts while you sleep. These pauses can happen 5 to 30 or more times per hour, all night long, pulling you out of the deep, restful sleep stages your body needs to recover. An estimated 936 million adults worldwide between the ages of 30 and 69 have at least mild sleep apnoea, and roughly 425 million have moderate-to-severe forms.
Types of Sleep Apnoea
There are two main types, and the difference comes down to why you stop breathing.
Obstructive sleep apnoea (OSA) is by far the most common. It happens when the soft tissue at the back of your throat physically collapses and blocks your airway. When you’re awake, muscles in your throat actively hold this airway open. When you fall asleep, that muscle activity drops. For most people, the airway stays open anyway. But if your airway is already narrower than average (due to anatomy, excess weight around the neck, or other factors), losing that muscle tone is enough to cause a full collapse. Your chest and abdomen keep trying to breathe, pushing against a closed airway, but no air gets through until your brain briefly rouses you to reopen it.
Central sleep apnoea (CSA) is less common and works differently. Your airway isn’t blocked. Instead, your brain temporarily stops sending the signal to breathe. During a central apnoea event, your chest and abdomen don’t move at all because the muscles never receive the instruction to contract. CSA is more often linked to heart failure, stroke, or the use of certain medications.
Some people have both types simultaneously, sometimes called mixed or complex sleep apnoea.
Common Symptoms
The hallmark sign of sleep apnoea is loud snoring, though not everyone who snores has the condition. What distinguishes sleep apnoea snoring is that it’s punctuated by silent pauses (the moments you stop breathing) followed by gasping or choking sounds as breathing restarts. A bed partner is often the first to notice these episodes.
Because your sleep is being fragmented dozens of times per hour, the daytime effects can be significant:
- Excessive daytime sleepiness, even after a full night in bed
- Morning headaches
- Waking up with a dry mouth
- Difficulty paying attention or concentrating
- Irritability
- Trouble staying asleep throughout the night
Many people with sleep apnoea don’t remember waking up during the night. The arousals are so brief that your conscious brain never fully registers them, which is why the condition can go undiagnosed for years.
Who Is Most at Risk
Excess weight is the single biggest risk factor for obstructive sleep apnoea. Fat deposits around the neck and upper airway narrow the space available for air to flow. A neck circumference greater than 17 inches in men or 16 inches in women is one practical marker that correlates with higher risk. In the U.S., about 26% of adults aged 30 to 70 have at least mild OSA, and 10% have moderate-to-severe cases.
Other factors that raise your risk include being male (though the gap narrows after menopause), having a naturally narrow airway or a recessed jaw, a family history of the condition, smoking, nasal congestion, and regular alcohol use (which relaxes throat muscles further during sleep). Age also plays a role, with prevalence climbing in middle-aged and older adults.
Health Risks of Untreated Sleep Apnoea
Sleep apnoea does more than leave you tired. Each time your breathing stops, your blood oxygen level drops. Your body responds with a surge of stress hormones that spikes your heart rate and blood pressure. Repeated hundreds of times a night, over months and years, this takes a measurable toll on your cardiovascular system.
A large study following patients over a median of seven years found that people with OSA had a 57% higher risk of major cardiac events compared to those without OSA, even after adjusting for other health factors. Among people with poorly controlled high blood pressure, that risk climbed to 93%. Sleep apnoea is also linked to insulin resistance, type 2 diabetes, and problems with memory and mood. The chronic sleep deprivation alone raises the risk of car accidents and workplace injuries.
How Sleep Apnoea Is Diagnosed
Diagnosis relies on measuring what happens while you sleep. The gold standard is an overnight sleep study called polysomnography, performed in a sleep lab. Sensors track your brain waves, eye movements, heart rate, blood oxygen levels, breathing patterns, chest and abdominal movement, body position, limb movements, and snoring. This comprehensive picture lets a specialist identify exactly what type of apnoea you have and how severe it is.
For many people suspected of having straightforward obstructive sleep apnoea, a home sleep test is a simpler alternative. These portable devices record your breathing rate, airflow, oxygen levels, and heart rate. They’re less detailed than a lab study but sufficient to confirm OSA in most cases.
Severity Scoring
The key number from any sleep study is the Apnea-Hypopnea Index (AHI), which counts how many times per hour your breathing fully stops or significantly decreases. According to Harvard Medical School’s classification:
- Mild: 5 to 14 events per hour
- Moderate: 15 to 29 events per hour
- Severe: 30 or more events per hour
Fewer than 5 events per hour is considered normal.
Treatment Options
The most widely used treatment for moderate-to-severe obstructive sleep apnoea is a CPAP machine (continuous positive airway pressure). It delivers a steady stream of pressurized air through a mask you wear over your nose, mouth, or both while you sleep. This air pressure acts as a splint, keeping your throat open so it can’t collapse. It works well when used consistently, but many people struggle with comfort, mask fit, or the noise, especially in the first few weeks.
A BiPAP machine works on the same principle but uses two pressure settings: a higher one when you inhale and a lower one when you exhale. This can feel more natural and is sometimes prescribed when CPAP pressure needs to be high or when someone has difficulty exhaling against constant pressure.
For people with mild-to-moderate OSA who can’t tolerate a CPAP, a mandibular advancement device is an effective alternative. This is a custom-fitted oral appliance, similar to a sports mouthguard, that holds your lower jaw slightly forward to keep the airway open. A five-year follow-up study found that these devices maintained a treatment success rate of 52% overall, with 46% of users achieving fewer than 10 breathing events per hour. People with a recessed jaw or a smaller neck circumference tend to respond best to this approach. Patient satisfaction and adherence remained strong over the five years of the study.
Lifestyle changes also make a real difference, particularly for milder cases. Losing weight reduces fat around the airway and can significantly lower AHI scores, sometimes resolving the condition entirely. Sleeping on your side rather than your back prevents gravity from pulling throat tissue into the airway. Avoiding alcohol and sedatives before bed helps maintain muscle tone in the throat. For some people with specific anatomical issues, surgical options to widen the airway or reposition the jaw may be considered.
What Living With Sleep Apnoea Looks Like
Sleep apnoea is a chronic condition for most people, but it’s highly manageable. The biggest hurdle is usually getting used to treatment. With CPAP, it often takes a few weeks of adjusting mask styles and pressure settings before it feels comfortable. Most people report noticeably better energy, mood, and mental clarity within the first week or two of consistent use.
Regular follow-ups with a sleep specialist help ensure your treatment is still working. Weight changes, aging, and other health shifts can alter your AHI over time, and your pressure settings or device type may need to be updated. Many modern CPAP machines track your usage and breathing events automatically, making it easy to monitor progress between appointments.