What Is Obstructive Sleep Apnoea?

Introduction

Obstructive sleep apnoea (OSA) is one of the most common — and frequently undiagnosed — sleep disorders.

It occurs when the airway repeatedly narrows or collapses during sleep, causing breathing to stop and start throughout the night.

Many people with sleep apnoea are unaware they have it. They may simply feel tired, unfocused, or irritable without understanding the underlying cause. If you often wonder why you are always tired even after 8 hours of sleep, obstructive sleep apnoea could be a contributing factor.

Understanding what obstructive sleep apnoea is — and how it affects the body — is the first step toward better sleep and better health.

What Happens During Obstructive Sleep Apnoea?

When we fall asleep, the muscles in the throat naturally relax.

In obstructive sleep apnoea:

• The airway becomes too narrow
• The airway may partially or completely collapse
• Airflow becomes restricted or stops entirely

When breathing pauses:

• Oxygen levels in the blood drop
• The brain senses this reduction
• A brief awakening occurs to reopen the airway

These interruptions can happen dozens — even hundreds — of times per night.

Most awakenings are so brief that the person does not remember them. However, they prevent deep, restorative sleep.

Why Does the Airway Collapse?

The collapse typically occurs due to a combination of factors:

• Relaxation of throat muscles during sleep
• Excess tissue around the airway
• Natural airway anatomy
• Reduced muscle tone with ageing

Certain risk factors increase the likelihood of obstructive sleep apnoea, including:

• Excess weight
• Family history
• Male sex (though women are also affected)
• Age over 40
• Structural jaw or airway differences

Common Symptoms of Obstructive Sleep Apnoea

Night-Time Symptoms

• Loud, persistent snoring
• Pauses in breathing observed by a partner
• Choking or gasping during sleep
• Restless or fragmented sleep

If you or your partner have noticed loud snoring that may be a sign of sleep apnoea, it is worth investigating further.

Daytime Symptoms

• Waking up unrefreshed
• Excessive daytime sleepiness
• Morning headaches
• Brain fog or poor concentration
• Irritability or mood changes

It is important to note that not everyone with sleep apnoea snores — and not all snoring indicates sleep apnoea.

How Common Is It?

Obstructive sleep apnoea affects millions of adults worldwide.

Research suggests that a significant proportion of moderate-to-severe cases remain undiagnosed.

Because symptoms can develop gradually, many people assume their fatigue or snoring is "normal."

Why Does Sleep Apnoea Matter?

Untreated obstructive sleep apnoea can place ongoing strain on the body.

Repeated drops in oxygen and stress hormone surges may increase the risk of:

• High blood pressure
• Heart disease
• Stroke
• Type 2 diabetes
• Cognitive decline
• Motor vehicle accidents due to sleepiness

To learn more about the serious consequences of leaving this condition unaddressed, read our article on what happens if sleep apnoea is left untreated. Early recognition and treatment can significantly reduce these risks and improve quality of life.

How Is Obstructive Sleep Apnoea Diagnosed?

Diagnosis typically involves a sleep study.

This may be:

• A home-based sleep test
• An overnight laboratory study

The results measure breathing interruptions, oxygen levels, and sleep patterns.

The severity of sleep apnoea is often classified using the Apnoea–Hypopnoea Index (AHI), which reflects the number of breathing interruptions per hour.

The Good News: It Is Treatable

Obstructive sleep apnoea is highly treatable.

Treatment options may include:

• Continuous positive airway pressure (CPAP) therapy
• Oral appliances
• Weight management
• Positional therapy
• In selected cases, surgical intervention

Many patients experience dramatic improvements in energy, concentration, and overall health once treatment begins.

When Should You Consider an Assessment?

You may benefit from a sleep evaluation if you:

• Snore loudly and regularly
• Wake feeling unrefreshed
• Experience excessive daytime sleepiness
• Have high blood pressure that is difficult to control
• Feel sleepy while driving

Persistent symptoms should not be ignored.

Conclusion

Obstructive sleep apnoea is a common but often overlooked condition that disrupts breathing during sleep.

While it may present subtly — through fatigue or snoring — its impact on long-term health can be significant.

The encouraging news is that effective treatment can dramatically improve sleep quality and overall wellbeing.

Understanding what obstructive sleep apnoea is empowers you to take the next step toward healthier sleep.

References

1. American Academy of Sleep Medicine. https://aasm.org
2. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov
3. Mayo Clinic. https://www.mayoclinic.org
4. Johns Hopkins Medicine. https://www.hopkinsmedicine.org