What Is Sleep Apnea and How Is It Treated?

A Condition That Stops Your Breathing Hundreds of Times a Night

Imagine your breathing stopping dozens — sometimes hundreds — of times every night while you sleep, each pause starving your brain and heart of oxygen. That is the reality for people with sleep apnea, one of the most common and most underdiagnosed conditions in the world. Estimates suggest nearly one billion adults aged 30–69 have some form of obstructive sleep apnea globally, yet the vast majority remain undiagnosed.

What Exactly Is Sleep Apnea?

Sleep apnea is a chronic breathing disorder characterised by repeated interruptions in breathing during sleep. These pauses, called apneas, can last from a few seconds to over a minute and may happen 30 or more times per hour in severe cases. Each time breathing stops, blood oxygen levels drop, and the brain triggers a brief arousal to restart breathing — often with a loud gasp or snort. Most people have no memory of these awakenings.

There are three main types:

• Obstructive sleep apnea (OSA) — the most common form, caused when the throat muscles relax and physically block the upper airway.
• Central sleep apnea (CSA) — occurs when the brain fails to send the correct signals to the muscles that control breathing.
• Complex (mixed) sleep apnea — a combination of both, sometimes developing in patients being treated for OSA.

Why Does the Airway Collapse?

In obstructive sleep apnea, the problem is mechanical. During sleep, muscles throughout the body relax — including those in the throat and tongue. In people with anatomical risk factors such as a narrow airway, large tonsils, or excess weight around the neck, this relaxation allows the soft tissue to fall inward and partially or completely block airflow. Obesity is the single biggest modifiable risk factor; as the prevalence of obesity has risen over recent decades, so has the prevalence of sleep apnea.

Other risk factors include being male, being over 40, smoking, alcohol consumption, and a family history of the condition. Women's risk rises significantly after menopause.

The Health Consequences

Untreated sleep apnea does far more than cause snoring and daytime fatigue. Each apnea episode triggers a cascade of physiological stress: oxygen levels plummet, the heart rate spikes, and stress hormones flood the body. Over time, this repeated nightly assault damages the cardiovascular system.

According to the American Heart Association, obstructive sleep apnea increases the risk of heart failure by 140%, stroke by 60%, and coronary heart disease by around 30%. Research published in the Journal of the American College of Cardiology found that for every measurable reduction in blood oxygen during sleep, cardiovascular event risk rose by 45%.

Beyond the heart, untreated sleep apnea is associated with cognitive impairment, depression, type 2 diabetes, and an elevated risk of traffic accidents caused by excessive daytime sleepiness.

How Is It Diagnosed?

The gold standard for diagnosis is a polysomnography (sleep study), conducted either in a hospital sleep lab or increasingly with home-based monitoring devices. The key metric is the Apnea-Hypopnea Index (AHI) — the average number of breathing interruptions per hour. An AHI of 5–14 indicates mild sleep apnea; 15–29 is moderate; 30 or above is severe.

Treatments: From Masks to Pills

For decades, the standard treatment for moderate to severe OSA has been CPAP (Continuous Positive Airway Pressure) therapy. A CPAP machine delivers pressurised air through a mask worn over the nose or mouth, physically keeping the airway open throughout the night. When used consistently, CPAP is effective in more than 80% of cases and has even been shown to reverse some of the brain damage caused by severe untreated OSA.

However, many patients struggle with the mask's discomfort and noise, leading to poor compliance. Alternatives include:

• Oral appliances — custom dental devices that reposition the jaw and tongue to keep the airway open.
• Positional therapy — for patients whose apnea worsens when lying on the back.
• Surgery — including removal of tonsils or adenoids, or procedures to stiffen or reposition soft tissue.
• Hypoglossal nerve stimulation — an implantable device that electrically stimulates the tongue to prevent airway collapse.

A significant breakthrough emerged from a large European phase 2 trial published in The Lancet: the drug sulthiame, previously used as an epilepsy medication, reduced breathing interruptions by up to 47% in patients with moderate to severe OSA. The drug works by stabilising breathing signals in the brain, addressing the neurological instability that contributes to airway collapse. If confirmed in phase 3 trials, it could become the first oral pill approved specifically for sleep apnea — a major advance given how many patients cannot tolerate CPAP.

Who Should Get Tested?

Anyone who snores loudly, wakes frequently during the night, experiences morning headaches, or feels persistently tired despite seemingly adequate sleep should consider speaking to a doctor. Bed partners who notice breathing pauses or gasping sounds are often the first to raise the alarm. Given the serious cardiovascular consequences of untreated sleep apnea, early diagnosis and treatment can be genuinely life-saving.