Overview
Obstructive sleep apnoea (OSA) is a condition where the throat repeatedly collapses during sleep, temporarily stopping breathing. Each episode causes brief arousal, disrupting sleep architecture. People with OSA are unaware of these events but suffer poor-quality sleep, leading to significant daytime sleepiness. Untreated OSA increases the risk of hypertension, heart disease, stroke, and road traffic accidents.
How common is it?
OSA affects approximately 1.5 million adults in the UK, though the majority are undiagnosed. It is more common in overweight men, but can affect women, children, and people of any weight. Prevalence increases with age and BMI.
Causes and risk factors
During sleep, muscle tone decreases. In susceptible individuals, the upper airway collapses inward, blocking airflow. The brain detects falling oxygen levels and arouses the person enough to restore muscle tone and airway opening.
Common risk factors
- Obesity (excess fat around the neck compresses the airway)
- Male sex
- Age (muscle tone decreases)
- Large neck circumference (above 43cm in men, 38cm in women)
- Alcohol, sedatives, and muscle relaxants (worsen muscle tone)
- Anatomical features: retrognathia, enlarged tonsils, narrow airway
- Nasal obstruction
- Family history
- Smoking
- Hypothyroidism and acromegaly
Symptoms
- Loud, disruptive snoring
- Witnessed pauses in breathing during sleep (apnoeas)
- Gasping, snorting, or choking during sleep
- Excessive daytime sleepiness (falling asleep inappropriately)
- Waking with headaches
- Poor concentration and memory
- Mood changes: irritability, depression
- Nocturia
- Reduced libido
When to see a doctor
See a GP for unexplained excessive daytime sleepiness, especially with snoring and witnessed apnoeas. Driving while excessively sleepy is dangerous and potentially illegal — inform the DVLA and do not drive until treated.
Diagnosis
Epworth Sleepiness Scale questionnaire. Overnight sleep study: ambulatory oximetry (home), limited channel sleep study, or full polysomnography (gold standard). Apnoea-Hypopnoea Index (AHI) classifies severity: mild 5 to 14, moderate 15 to 29, severe 30 or more events per hour.
Treatments
Continuous positive airway pressure (CPAP)
A mask worn during sleep delivers pressurised air to keep the airway open. Highly effective — eliminates apnoeas in most patients when used consistently. Compliance is the main challenge; modern auto-CPAP devices are more comfortable.
Weight loss
Weight loss of 10 to 15% can resolve OSA in obese patients. Bariatric surgery can achieve remission in most cases of severe obesity-related OSA. GLP-1 receptor agonists (tirzepatide) shown to reduce AHI by 50% in recent trials.
Mandibular advancement device (MAD)
Custom-fitted oral device worn at night that advances the lower jaw and opens the airway. Effective for mild to moderate OSA. Less effective than CPAP but better tolerated by some patients.
Positional therapy
For position-dependent OSA (only occurring on the back), positional devices or sleeping on one side can be effective.
Surgery
Tonsillectomy in children with adenotonsillar hypertrophy. Uvulopalatopharyngoplasty (UPPP) for adults with specific anatomy — variable success. Hypoglossal nerve stimulation (Inspire) is a newer implantable device for CPAP-intolerant patients.
Self-care and lifestyle
- Lose weight if overweight — the single most effective lifestyle intervention
- Avoid alcohol in the 3 to 4 hours before bed
- Sleep on your side rather than your back
- Stop smoking
- Treat nasal congestion to reduce upper airway resistance
Prevention
Maintaining a healthy weight throughout life is the most important preventive measure. Treating nasal congestion and avoiding alcohol and sedatives before sleep also reduce risk.