What Is Sleep Apnoea? Symptoms and Treatments

Sleep apnoea is a common but frequently undiagnosed condition in which breathing repeatedly stops and starts during sleep, disrupting oxygen levels and preventing restorative rest. It affects an estimated 1.5 million adults in the UK, yet many remain unaware they have it. Understanding what sleep apnoea is, how it presents, who is at risk, and what treatments are available is essential for protecting long-term health. This article covers the key facts, from recognising symptoms to navigating NHS diagnosis and evidence-based treatment options.

What exactly is sleep apnoea and how does it affect your body?

Sleep apnoea causes repeated breathing interruptions during sleep, lowering blood oxygen and fragmenting sleep architecture. Over time, this raises the risk of hypertension, atrial fibrillation, type 2 diabetes, and stroke.

Sleep apnoea is a condition in which breathing repeatedly stops and starts during sleep, depriving the body of oxygen and disrupting restorative rest. The most common form, obstructive sleep apnoea (OSA), occurs when the muscles at the back of the throat relax excessively, causing the airway to narrow or close entirely.^[1][10] A less common form, central sleep apnoea (CSA), arises when the brain fails to send the correct signals to the muscles that control breathing. CSA is often associated with underlying conditions such as heart failure or the use of opioid medicines, and its management differs from that of OSA. A mixed form combining both mechanisms also exists.

During each apnoeic episode, blood oxygen levels fall and carbon dioxide rises. The brain detects this and briefly rouses the sleeper, often without their awareness, to restore normal breathing. These micro-arousals can occur dozens or even hundreds of times per night, preventing the deep, slow-wave and REM sleep stages that are essential for physical and cognitive recovery.

Over time, the cumulative effect of repeated oxygen dips and sleep fragmentation places significant strain on the cardiovascular system. Untreated OSA is associated with an increased risk of hypertension, atrial fibrillation, type 2 diabetes, and stroke, as outlined in NICE guideline NG202 and supported by NHS clinical guidance.^[2][4] The condition also impairs daytime cognitive function, mood regulation, and workplace performance, making it a meaningful public health concern rather than simply a nuisance.

What are the most common signs and symptoms to watch for?

The most recognisable signs are loud snoring and witnessed breathing pauses, but daytime sleepiness, morning headaches, poor concentration, and nocturia are equally important indicators. Women and those with central sleep apnoea may present with subtler symptoms such as fatigue or insomnia.

Loud, persistent snoring accompanied by witnessed pauses in breathing are the most recognisable signs of obstructive sleep apnoea, though not everyone who snores has the condition. Partners or family members are often the first to notice these breathing interruptions, which may end with a loud gasp, snort, or choking sound as the sleeper briefly wakes to reopen the airway.

Daytime symptoms are equally important and are often what prompt people to seek medical advice. These include:

• Excessive daytime sleepiness, sometimes severe enough to cause drowsiness while driving or at work

• Unrefreshing sleep, even after a full night in bed

• Morning headaches, which may relate to overnight oxygen desaturation, sleep fragmentation, and in some cases raised carbon dioxide levels

• Difficulty concentrating and memory problems

• Irritability, low mood, or symptoms consistent with depression

• Nocturia (waking repeatedly to urinate during the night)

• Dry mouth or sore throat on waking

It is worth noting that some people, particularly women and those with central sleep apnoea, present with subtler symptoms such as insomnia, fatigue, or mood disturbance rather than classic snoring. This can lead to delayed diagnosis.

Driving safety: If you experience excessive daytime sleepiness, you must not drive until the problem has been assessed and, where applicable, effectively treated. Under DVLA guidance, people with obstructive sleep apnoea hypopnoea syndrome (OSAHS) who have excessive sleepiness are required to notify the DVLA and must not drive until their symptoms are controlled. If you or someone close to you notices any combination of these symptoms, speak to a GP promptly. Untreated sleep apnoea carries real health risks, and early assessment is straightforward.

Who is most at risk of developing sleep apnoea in the UK?

Obesity, male sex, increasing age, and a larger neck circumference are the strongest risk factors for OSA in the UK. Anatomical features, alcohol use, smoking, and conditions such as hypothyroidism or PCOS also increase risk.

Obstructive sleep apnoea is more common than many people realise. Asthma + Lung UK (formerly the British Lung Foundation, which rebranded in 2022) estimates that around 1.5 million adults in the UK have the condition, though a significant proportion remain undiagnosed. Several factors increase an individual's likelihood of developing it.

Key risk factors include:

• Excess weight or obesity: Fat deposits around the upper airway narrow the breathing passage and are one of the strongest modifiable risk factors

• Male sex: OSA is diagnosed more commonly in men than in women, though the gap narrows after the menopause; NICE NG202 and NHS guidance note this sex difference

• Age: Prevalence rises with age, particularly from middle age onwards, as muscle tone in the throat decreases

• Neck circumference: A larger neck circumference is associated with higher risk; commonly used screening tools such as STOP-BANG use thresholds of approximately 43 cm (17 inches) in men and 41 cm (16 inches) in women, though thresholds may vary by tool and clinical context^[14][16]

• Anatomical features: A narrow airway, enlarged tonsils or adenoids, a recessed jaw, or a deviated nasal septum can all contribute

• Alcohol and sedative use: These relax throat muscles and worsen airway collapse during sleep

• Smoking: Irritation and inflammation of the upper airway increase risk

• Family history: A genetic predisposition to craniofacial structure or obesity can run in families

• Certain medical conditions: Hypothyroidism, acromegaly, and polycystic ovary syndrome (PCOS) are associated with higher OSA prevalence^[19][20]

Ethnicity may also play a role, with some evidence suggesting differences in OSA prevalence across ethnic groups in the UK, partly related to craniofacial anatomy, though further UK-specific research is ongoing. Addressing modifiable risk factors, particularly weight, remains one of the most effective preventive strategies.

How is sleep apnoea diagnosed on the NHS?

Diagnosis begins with a GP assessment using tools such as the Epworth Sleepiness Scale, followed by referral for a sleep study measuring the Apnoea-Hypopnoea Index (AHI). An AHI of 5 to 14 indicates mild OSA, 15 to 29 moderate, and 30 or above severe OSA.

Sleep apnoea is diagnosed through a combination of clinical assessment and sleep studies, and the process typically begins with a GP consultation. The GP will take a detailed history of symptoms, ask about witnessed apnoeas, and may use validated screening tools such as the Epworth Sleepiness Scale or the STOP-BANG questionnaire to assess the likelihood of OSA. Blood pressure measurement and body mass index (BMI) calculation are also standard, given their relevance to risk.

If OSA is suspected, the GP will refer the patient to a specialist sleep service. NICE guideline NG202 (2021) recommends considering respiratory polygraphy (a limited-channel sleep study) for adults with suspected OSA; this may be performed at home or within the sleep service depending on patient factors and local service configuration.^[2][4] A home sleep study typically involves wearing a small device overnight that records:

• Oxygen saturation (via a finger probe)

• Airflow through the nose and mouth

• Chest and abdominal movement

• Heart rate

• Body position

The results are used to calculate the Apnoea-Hypopnoea Index (AHI), which measures the average number of breathing interruptions per hour of sleep. An AHI of 5 to 14 indicates mild OSA, 15 to 29 moderate OSA, and 30 or above severe OSA. Some UK sleep services report results using the Oxygen Desaturation Index (ODI) or the Respiratory Event Index (REI) depending on the equipment used; your sleep service will explain which measure applies to your results. In-laboratory polysomnography, which records a broader range of physiological signals overnight in a sleep centre, is reserved for complex cases or where a home study is inconclusive. Diagnosis should always be made by a clinician with appropriate expertise, not on the basis of a consumer wearable device alone.

What treatment options are available and do they really work?

CPAP is the most evidence-based treatment for moderate to severe OSA, consistently reducing sleepiness and blood pressure. Mandibular advancement devices, lifestyle changes, and in selected cases surgery are also recommended options under NICE NG202.

Effective treatments for sleep apnoea exist across a spectrum, and the right approach depends on severity, underlying causes, and individual circumstances. For many people, a combination of lifestyle changes and a device-based therapy produces substantial improvement.

Lifestyle modifications are recommended for all patients and include:

• Weight loss: Even modest reductions in weight can significantly reduce AHI scores in overweight individuals

• Reducing alcohol intake, particularly in the evening

• Stopping smoking

• Positional therapy for those whose apnoeas occur predominantly when lying on their back

Continuous positive airway pressure (CPAP) is the most evidence-based treatment for moderate to severe OSA and is recommended by NICE NG202.^[2][4] A CPAP machine delivers a gentle, continuous stream of pressurised air through a mask worn during sleep, keeping the airway open and preventing collapse. Evidence from clinical trials and systematic reviews consistently shows that regular CPAP use reduces daytime sleepiness, lowers blood pressure, and improves quality of life.^[12] Adherence is the main challenge, and NHS sleep services offer support to help patients adjust to the device.

Mandibular advancement devices (MADs) are custom-fitted oral appliances that hold the lower jaw slightly forward, widening the airway. NICE NG202 recommends them as an alternative for mild to moderate OSA or for patients who cannot tolerate CPAP.^[2][4] Custom-fitted devices provided by a suitably trained dental professional are more effective than over-the-counter versions.^[17][18]

Surgical options, such as tonsillectomy or procedures to correct anatomical abnormalities, are considered in selected cases, particularly in children or adults with a clear structural cause.

Central sleep apnoea is managed differently from OSA, with treatment focused on addressing the underlying cause (such as heart failure or opioid use) and guided by specialist assessment.

Driving and DVLA notification: People with OSAHS who have excessive daytime sleepiness must not drive until their symptoms are effectively controlled by treatment. Where DVLA notification is required, this should be done before returning to driving. Your sleep service or GP can advise on when it is safe to drive again.

For patients exploring weight management as part of their OSA treatment plan, a GP or specialist can advise on appropriate options. Bolt Pharmacy is a GPhC-registered UK online pharmacy offering online weight-management consultations, with prescriber review and pharmacist support; weight-management treatments are only considered where clinically appropriate following a consultation. Regardless of the treatment pathway chosen, regular follow-up with an NHS sleep service is important to monitor progress and adjust therapy as needed.

Scientific References

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4. NG202 Chapter 1: Obstructive sleep apnoea/hypopnoea syndrome.
5. NG202 Chapter: Rationale and impact.
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