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What is sleep apnea?

If your patients are exhausted, their partners complain about their snoring; if they are falling asleep at work or while driving, they may have sleep apnea. Early intervention could save lives.

What is sleep apnea?

Sleep apnea (also spelt apnoea) is a dyssomnia caused by relaxed pharyngeal muscles collapsing into the airway during deep sleep. The patient will snore, stop breathing, awaken a little, then fall asleep again. This lack of sleep and oxygen leads to a sense of exhaustion.

The patient may not know they suffer from sleep apnea because 80% of the people with the condition are believed to be undiagnosed 1. Up to 6% of the population suffers from sleep apnea 2,3 – increasing to 77% in obese people 4 – and many people do not know that they have it. 

Patients are often referred by their partners due to snoring or decreased sex drive. Some will see their doctor following an accident caused by falling asleep at the wheel.

There are three types of sleep apnea:

  • Obstructive sleep apnea (OSA) – the most common - where relaxation of the pharyngeal muscles interferes with the airway, causing breathing to stop.
  • Central sleep apnea – not as common as OSA - where the brain or nerves fail to trigger the breathing muscles to breathe.
  • Combination – or complex sleep apnea - where obstructive and central sleep apnea occur together.

Relative severities of sleep apnea

The physiological process of sleep apnea – the closing of the airway, waking up and breathing – is normal when it occurs infrequently. However, more than five interruptions an hour indicate sleep apnea:

Normal Fewer than 5 interruptions an hour.
Mild sleep apnea Between 5 and 15 interruptions an hour.
Moderate sleep apnea

Between 15 to 30 interruptions an hour.

Severe sleep apnea

More than 30 interruptions an hour.


Affected populations

Sleep apnea occurs in all age groups and body morphologies but several factors can dramatically increase the chances:

  • Obesity – around 77% of obese patients suffer from sleep apnea 4.
  • Advanced age – sleep apnea is more likely in people over 50.
  • Thyroid conditions or a goitre that constricts the neck or airway.
  • Physical characteristics of the throat such as enlarged tonsils, a small airway, or small nasal passages.
  • Ingestion of alcohol, sedatives or sleeping pills before bed.


The presence of two or three common sleep apnea symptoms indicates that a sleep test may be in order. Symptoms include:

  • Snoring – many sleep apnea patients are referred to a doctor because their snoring keeps their partners awake.
  • Feeling sleepy during the day – some seek treatment after falling asleep while driving or at work.
  • Poor concentration.
  • Feeling irritable or moody.
  • A reduced sex drive or erectile dysfunction.
  • Frequent urination at night.
  • Nightmares.


Co-morbidities of sleep apnea include:

Poor cardiovascular health 6,7

Hypertension 8,9
Stroke 9

Type 2 diabetes 10,11,12,13


Self assessment

Help your patients assess their own chances of having sleep apnea and whether further testing is required with this STOP-Bang quiz.


1. Obstructive sleep apnea – a guide for GP’s, British Lung Foundation (NHS)

2. Chronic respiratory diseases, The World Health Organizaton

3. Reawakening Australia: the economic cost of sleep disorders in Australia, 2010, A report for the Sleep Health Foundation by Deloitte Access Economics© 2011 Deloitte Access Economics Pty Ltd

4. O’Keefe,, Evidence supporting routine Polysomnography before bariatric surgery, in,Obesity Surgery, January 2014

5. Sleep breathing disorders, in, European Respiratory Society Whitebook, Chapter 23

6. Patient information series – Sleep mini series #4, in, Obstructive Sleep Apnea and Heart Disease, American Thoracic Society

7. Dincer HE, O’Neill W (2006): Deleterious effects of sleep-disordered breathing on the heart and vascular system. Respiration 73(1): 124-130

8. Peppard PE, Young T, Palta M, Skatrud J (2000): Prospective study of the association between sleep-disordered breathing and hypertension. NEJM 342(19): 1378-1384

9. Logan, High prevalence of unrecognized sleep apnoea in drug-resistant hypertention, in, Journal of Hypertension, 2001

10. Einhorn,, Prevalence of sleep apnea in a population of adults with type 2 diabetes Mellitus, in, Endocrine Practice, 2007; 13(4):355-362

11. Meslier N, Gagnadoux F, Giraud P, Person C, Ouksel H, Urban T, Racineux JL (2003): Impaired glucose-insulin metabolism in males with obstructive sleep apnoea syndrome. Eur Respir J 22(1): 156-160

12. Bottini P, Dottorini ML, Cristina Cordoni M, Casucci G, Tantucci C (2003): Sleep-disordered breathing in nonobese diabetic subjects with autonomic neuropathy. Eur Respir J 22: 654- 660

13. Elmasry A, Lindberg E, Berne C, Janson C, Gislason T, Awad Tageldin M, Boman G (2001): Sleep-disordered breathing and glucose metabolism in hypertensive men: a population-based study. J Intern Med 249(2): 153-161