Sleep-related breathing disorders and long-term health
The Complications of Untreated Obstructive Sleep Apnoea
Obstructive sleep apnoea is more than loud snoring. Repeated narrowing or closure of the upper airway can fragment sleep, reduce blood oxygen levels and place additional stress on the brain, cardiovascular system and metabolism. Untreated disease can affect alertness, safety, mood, relationships and long-term health.
- Daytime sleepiness
- Driving risk
- High blood pressure
- Heart rhythm problems
- Memory and mood
- Surgical risk
Treatment is available
Lifestyle measures, CPAP, mandibular advancement devices and selected specialist interventions can improve breathing during sleep and reduce daytime symptoms.
Snoring alone does not prove OSA
Many people snore without sleep apnoea. Concern rises when snoring is accompanied by witnessed breathing pauses, choking, unrefreshing sleep or excessive daytime sleepiness.
What is obstructive sleep apnoea?
When the airway closes, the brain briefly lightens sleep or wakes the person sufficiently to restore breathing. These arousals may happen repeatedly without being remembered the next morning.
Common night-time features include:
- loud or disruptive snoring;
- witnessed pauses in breathing;
- gasping, choking or snorting during sleep;
- frequent waking or restless sleep;
- dry mouth on waking;
- morning headache;
- frequent night-time urination.
Daytime features may include unrefreshing sleep, excessive sleepiness, fatigue, poor concentration, reduced memory, irritability and diminished work performance.
For a broader explanation of symptoms, testing and treatment, read the London Chest Specialist guide to obstructive sleep apnoea and snoring .
Why can untreated OSA cause complications?
The health effects of OSA arise from several processes occurring repeatedly throughout the night.
Intermittent hypoxia
Repeated falls and recoveries in oxygen can promote sympathetic activation, oxidative stress and vascular dysfunction.
Sleep fragmentation
Frequent arousals reduce restorative sleep even when the person believes they remained asleep all night.
Pressure changes
Strong efforts to breathe against a closed airway alter pressure within the chest and may stress the heart.
Blood-pressure surges
Each obstructive event can trigger short-lived increases in heart rate and blood pressure.
Metabolic disruption
Poor sleep and intermittent hypoxia may influence insulin sensitivity, appetite and energy regulation.
Inflammation
Repeated physiological stress may contribute to chronic inflammatory and vascular changes.
Risk is not determined by the AHI alone
The apnoea–hypopnoea index records how often breathing events occur. Clinical risk also depends on oxygen desaturation, event duration, sleepiness, cardiovascular disease, age, weight and other medical conditions.
Daytime sleepiness, fatigue and reduced performance
Persistent tiredness
A person may wake feeling unrefreshed despite apparently spending enough hours in bed.
Poor concentration
Fragmented sleep can make reading, meetings, decision-making and sustained mental work more difficult.
Work impairment
Slower reaction time, reduced motivation and mistakes may affect professional performance.
Reduced activity
Fatigue can discourage exercise, making weight management and cardiovascular health more difficult.
Withdrawal
Persistent exhaustion may reduce interest in family, leisure and social activities.
Feeling unlike yourself
People sometimes describe reduced confidence, motivation and emotional resilience.
Fatigue and sleepiness are not identical
Fatigue is a sense of reduced energy or exhaustion. Sleepiness is a tendency to fall asleep. OSA may cause either, but persistent symptoms can also have other medical, psychological or lifestyle causes.
Cardiovascular complications
OSA is associated with several cardiovascular conditions. Intermittent oxygen desaturation, arousal-related stress responses and repeated blood-pressure surges are thought to contribute.
High blood pressure
Night-time effect
Obstructive events can cause repeated temporary surges in blood pressure during sleep.
Long-term association
OSA is associated with hypertension and is particularly relevant when blood pressure remains high despite several medicines.
Why assessment matters
Treating sleep apnoea may support overall blood-pressure management, alongside medication and lifestyle treatment.
Heart rhythm disorders
Atrial fibrillation
OSA is common in people with atrial fibrillation and may contribute to rhythm instability.
Night-time stress
Oxygen changes, autonomic surges and altered chest pressure can influence cardiac electrical activity.
Integrated care
Sleep apnoea should be considered alongside weight, blood pressure, alcohol intake and established cardiac treatment.
Stroke and vascular disease
Shared risk factors
OSA commonly coexists with obesity, hypertension, diabetes and cardiovascular disease.
Clinical association
Untreated OSA is associated with increased stroke and vascular risk, particularly in higher-risk patients.
After a stroke
OSA can affect rehabilitation through sleepiness, poor concentration and impaired cardiovascular control.
Heart failure
Mechanical stress
Attempts to breathe against a closed airway change pressure within the chest and increase cardiac workload.
Coexisting disease
Sleep-disordered breathing is common in heart failure, although obstructive and central events must be distinguished.
Specialist evaluation
Treatment should account for cardiac function, symptoms, sleep-study findings and the type of sleep apnoea.
Association does not mean that OSA is the only cause
Cardiovascular disease has many contributing factors. Treating OSA forms one part of wider care that may include blood-pressure control, cholesterol treatment, weight management, diabetes care, exercise and smoking cessation.
Metabolic health and weight
Insulin resistance
Fragmented sleep and intermittent hypoxia may reduce insulin sensitivity and make glucose regulation more difficult.
Type 2 diabetes
OSA is more prevalent among people with type 2 diabetes, and each condition may complicate management of the other.
Appetite regulation
Poor sleep can influence appetite, food choices and hormonal signals involved in hunger and fullness.
Reduced activity
Daytime fatigue can make regular exercise and weight management more difficult.
Bidirectional relationship
Excess weight can narrow the upper airway, while untreated OSA may make maintaining a healthy weight harder.
Obesity hypoventilation
Some people with obesity have inadequate ventilation during sleep or wakefulness in addition to OSA and need specialist assessment.
OSA can occur at any body size
Excess weight is an important risk factor, but craniofacial anatomy, tonsil size, nasal obstruction, age, menopause and other factors can contribute. A person should not be denied assessment simply because their weight is within a healthy range.
Memory, concentration and mental health
Restorative sleep supports attention, memory, emotional regulation and decision-making. Repeated disruption can affect these functions, although symptoms are not specific to OSA.
Cognitive symptoms
- poor concentration;
- forgetfulness;
- slower processing speed;
- difficulty making decisions;
- reduced attention during repetitive tasks.
Mood symptoms
- irritability;
- low mood;
- reduced motivation;
- anxiety symptoms;
- lower tolerance of stress.
Do not automatically attribute every symptom to sleep apnoea
Depression, anxiety, thyroid disease, anaemia, medication effects, insufficient sleep and many other conditions can produce similar symptoms. Persistent problems require an appropriately broad assessment.
Driving, workplace safety and accidents
Do not drive when excessive sleepiness makes driving unsafe
Excessive sleepiness can impair reaction time, attention and judgement. A person who is struggling to stay awake, has dozed at the wheel or feels unable to drive safely should stop driving and seek medical advice.
| Situation | Potential problem | Safer response |
|---|---|---|
| Driving | Microsleeps, delayed reaction time and loss of concentration | Stop driving if sleepy and follow medical and DVLA advice |
| Commercial driving | Long or monotonous journeys can magnify the consequences of sleepiness | Seek prompt specialist assessment and comply with vocational driving requirements |
| Machinery | Brief lapses of attention can cause serious workplace injury | Inform occupational health where relevant and avoid safety-critical work while impaired |
| Shift work | Circadian disruption and sleep restriction can worsen existing OSA-related symptoms | Review work patterns, sleep duration and treatment adherence |
| Medication or alcohol | Sedating substances can compound sleepiness and airway collapse | Check medicine warnings and avoid alcohol before sleep or driving |
DVLA requirements depend on severity and sleepiness
UK notification rules are specific. Confirmed moderate or severe obstructive sleep apnoea syndrome with excessive sleepiness must be reported to the DVLA. Other sleep conditions causing excessive sleepiness may also require notification. Patients should obtain individual medical advice and consult current GOV.UK guidance.
Relationships, intimacy and family life
Partner sleep disruption
Loud snoring, choking and repeated movement can fragment the partner’s sleep as well as the patient’s.
Separate bedrooms
Some couples sleep apart because of snoring, which can affect closeness and communication.
Irritability
Chronic tiredness can reduce patience and increase conflict at home.
Reduced libido
Fatigue, metabolic health and hormonal factors may affect sexual wellbeing.
Family anxiety
Witnessed choking or prolonged breathing pauses can be frightening for partners and relatives.
Shared improvement
Effective treatment can improve the sleeping environment and quality of life for both partners.
Surgery, sedation and medication risks
Airway management
OSA may coexist with anatomical features that make airway management more challenging.
Postoperative breathing
Breathing obstruction may worsen during recovery, especially after sedating medication or opioids.
Monitoring needs
Some patients require closer oxygen, breathing or cardiac monitoring after a procedure.
CPAP planning
Patients already using CPAP may be advised to bring their equipment and continue treatment around the operation.
Tell the surgical and anaesthetic team
Disclose diagnosed OSA, suspected OSA, previous sleep-study results, CPAP settings and treatment adherence before any planned operation or sedated procedure.
How is obstructive sleep apnoea diagnosed?
- Review symptoms The assessment considers snoring, witnessed apnoeas, choking, unrefreshing sleep, morning headaches, nocturia, fatigue and daytime sleepiness.
- Assess risk factors Weight, neck anatomy, nasal obstruction, alcohol, sedating medicines, menopause and relevant medical conditions are reviewed.
- Consider a screening questionnaire Tools such as STOP-Bang or the Epworth Sleepiness Scale may support assessment but do not confirm or exclude OSA.
- Arrange a sleep study Home respiratory polygraphy commonly records airflow, respiratory effort, oxygen saturation, pulse and body position.
- Use polysomnography when needed A more comprehensive study may record brain activity, eye movement, muscle activity, breathing and sleep stages.
- Interpret the whole study The clinician reviews event frequency, oxygen changes, symptoms, sleep time, body position and co-existing disease.
A normal home study does not always end the investigation
If clinical suspicion remains high, further testing may be needed. Limited studies can underestimate OSA when sleep time is uncertain or when technical signals are incomplete.
Can treatment reduce these risks?
| Treatment | How it may help | Important considerations |
|---|---|---|
| CPAP | Uses positive pressure to prevent upper-airway collapse during sleep | Correct mask fit, humidification and regular use improve effectiveness |
| Weight management | Can reduce airway narrowing and OSA severity in people with excess weight | OSA treatment should not necessarily be delayed while weight loss is attempted |
| Mandibular advancement device | Moves the lower jaw forward to enlarge the upper airway | Requires suitable teeth and professional dental fitting |
| Positional therapy | Reduces time sleeping on the back when OSA is position dependent | Not sufficient for every severity or pattern |
| Reduce alcohol and sedatives | May lessen airway collapse and sleep-related respiratory suppression | Prescribed medicines should not be stopped without clinical advice |
| Treat nasal obstruction | May improve nasal breathing and tolerance of CPAP | Nasal treatment alone does not reliably resolve most OSA |
| Surgery | May address enlarged tonsils, craniofacial narrowing or selected upper-airway obstruction | Suitability and outcomes vary according to anatomy |
| Hypoglossal nerve stimulation | Stimulates tongue muscles to reduce airway collapse | Reserved for carefully selected patients through specialist pathways |
CPAP is particularly effective for sleepiness
Regular CPAP use can prevent obstructive breathing events, improve sleep quality and reduce daytime sleepiness. Its effects on cardiovascular outcomes vary between patient groups, so other cardiovascular risk factors still need active treatment.
Do not buy or alter CPAP without appropriate assessment
Treatment should follow a confirmed diagnosis and include suitable settings, mask selection, monitoring and follow-up. Persistent symptoms despite treatment require review for leakage, insufficient use, residual events or another cause of sleepiness.
When should you seek assessment?
Night-time warning signs
- loud regular snoring;
- witnessed breathing pauses;
- gasping or choking;
- repeated waking;
- morning headaches;
- frequent nocturia.
Daytime warning signs
- excessive sleepiness;
- unrefreshing sleep;
- poor concentration;
- memory problems;
- irritability or low mood;
- sleepiness while driving or working.
Seek prompt medical advice when:
- you have fallen asleep or nearly fallen asleep while driving;
- a partner observes prolonged or frequent breathing pauses;
- sleepiness affects safety-critical work or machinery use;
- symptoms coexist with resistant hypertension, atrial fibrillation, stroke or heart failure;
- you have severe obesity with breathlessness, morning headache or suspected hypoventilation;
- surgery is planned and OSA is known or strongly suspected.
Frequently asked questions
Can untreated sleep apnoea shorten life expectancy?
Severe untreated OSA is associated with cardiovascular, metabolic and accident-related risks that may affect long-term health. An individual prognosis cannot be determined from the diagnosis alone because age, severity and other medical conditions also matter.
Does loud snoring mean that I have OSA?
No. Many people snore without OSA. The combination of loud snoring, witnessed apnoeas, choking, unrefreshing sleep or daytime sleepiness raises greater concern.
Can someone have OSA without snoring?
Yes. Snoring is common but not universal. Some people, particularly those who sleep alone, may be unaware of night-time breathing abnormalities.
Is there a cure for obstructive sleep apnoea?
Some underlying causes can improve substantially with weight reduction, tonsil surgery or another anatomical intervention. Many patients require ongoing management rather than a single permanent cure.
Is CPAP the only treatment?
No. Other options include weight management, mandibular advancement devices, positional therapy, management of nasal disease, selected surgery and hypoglossal nerve stimulation. The most appropriate choice depends on the individual case.
Does CPAP lower the risk of every cardiovascular complication?
CPAP reliably controls obstructive events when used and often improves sleepiness. Cardiovascular benefits vary across studies and patient groups, so blood pressure, diabetes, cholesterol, weight and other risks must still be managed.
Can OSA cause depression or anxiety?
OSA is associated with mood symptoms, but depression and anxiety have many possible causes. Both the sleep disorder and wider mental health should be assessed appropriately.
Can sleep apnoea affect memory?
Sleep fragmentation and sleepiness can affect attention, learning and memory. Persistent cognitive symptoms should not automatically be assumed to result from OSA alone.
Can OSA cause high blood pressure?
OSA is associated with hypertension and is particularly relevant in resistant hypertension. Several factors may contribute to an individual patient’s blood pressure.
Is OSA linked to atrial fibrillation?
Yes. OSA is common in people with atrial fibrillation and may contribute to rhythm instability through oxygen changes, pressure changes and autonomic activation.
Can untreated OSA make diabetes harder to control?
OSA is associated with insulin resistance and type 2 diabetes. Sleep treatment should complement—not replace—standard diabetes care.
Do I need to tell the DVLA?
Notification depends on the diagnosis, severity and whether excessive sleepiness affects driving. Confirmed moderate or severe OSA syndrome with excessive sleepiness must be reported. Consult current GOV.UK guidance and your clinician.
Can I drive while waiting for a sleep study?
You must not drive when excessive sleepiness makes driving unsafe. Obtain individual medical advice about driving and DVLA requirements rather than waiting for testing.
Should I tell my anaesthetist that I have OSA?
Yes. Tell the surgical and anaesthetic teams about diagnosed or suspected OSA, sleep-study results and CPAP use before surgery or sedation.
Can losing weight cure OSA?
Weight loss can substantially improve OSA in some people, but it may not eliminate disease completely. Repeat assessment may be needed before stopping established treatment.
Can thin people develop OSA?
Yes. Jaw structure, tongue size, tonsils, nasal obstruction, age and other anatomical or neurological factors can cause OSA at any body size.
What should I do if CPAP is uncomfortable?
Seek support rather than abandoning treatment. Mask changes, humidification, pressure adjustment, nasal treatment and gradual acclimatisation can improve tolerance.
Conclusion
Obstructive sleep apnoea is not simply a problem of noisy sleep. Repeated airway obstruction can fragment sleep, reduce oxygen levels and trigger physiological stress throughout the night.
Untreated OSA can contribute to excessive sleepiness, reduced concentration, impaired work performance, driving risk, relationship disruption and perioperative breathing problems.
It is also associated with hypertension, atrial fibrillation, stroke, heart failure, insulin resistance and type 2 diabetes. These conditions have multiple causes, but recognising and treating coexisting OSA may form an important part of overall medical care.
Diagnosis normally requires a structured clinical assessment and a sleep study. Treatment may include CPAP, weight management, a mandibular advancement device, positional therapy or selected specialist interventions.
Loud snoring accompanied by witnessed apnoeas, choking, unrefreshing sleep or excessive daytime sleepiness should not be ignored. Treatment is available, and identifying the condition can improve safety, quality of life and wider health management.
References and further information
- National Institute for Health and Care Excellence. Obstructive sleep apnoea/hypopnoea syndrome and obesity hypoventilation syndrome in over 16s. NICE guideline NG202. View the NICE guideline
- NHS. Sleep apnoea. Read the NHS information
- Driver and Vehicle Licensing Agency. Excessive sleepiness and driving. View current driving guidance
- Driver and Vehicle Licensing Agency. Assessing fitness to drive: excessive sleepiness and obstructive sleep apnoea syndrome. View guidance for medical professionals
- London Chest Specialist. Understanding obstructive sleep apnoea and snoring. Read the comprehensive OSA guide
- London Chest Specialist. Sleep hygiene and improving sleep quality. Read the sleep-hygiene guide
- London Chest Specialist. Appointment and investigation information. Read about consultations and sleep studies
Concerned About Snoring or Sleep Apnoea?
A specialist respiratory assessment can review snoring, witnessed breathing pauses, daytime sleepiness, cardiovascular risk factors and whether a sleep study or further treatment assessment is appropriate.
