Sleep disordered breathing
In our modern fast paced world, non-restorative sleep has become a common phenomenon. The third and latest edition of the International Classification of Sleep Disorders (ICSD-3) is the authoritative clinical text for the diagnosis of sleep disorders. These disorders are grouped into six major categories. The second of these is ‘Sleep Related Breathing Disorders’ (also known as sleep disorder breathing). Sleep loss from undiagnosed, and consequently untreated sleep related breathing disorders, can adversely affect health and well-being.
Sleep related breathing disorders are disorders that adversely affect a patient’s breathing while they are asleep. The most common sleep related breathing disorders are snoring and sleep apnoea. Obstructive sleep apnoea (OSA) is by far the most common form of sleep apnoea.
Snoring and Sleep Apnoea
Snoring is a common problem for many adults. It’s estimated that half of all adults snore at least occasionally and that 25 percent are habitual snorers. Snoring is a coarse sound made by vibrations of the soft palate and other tissue in the upper airway. It occurs when part of the throat air passage collapses and vibrates. When someone is asleep, the muscle tone in the tongue, soft palate and neighbouring structures decreases. This allows collapse and vibration of these structures when breathing, thereby causing snoring. Anything that obstructs the upper airway can contribute to snoring e.g. large adenoids or a large tongue. Light or occasional snoring is not a health threat if it doesn’t interrupt breathing.
It’s estimated that 30-50% of snorers actually suffer from sleep apnoea. Sleep apnoea occurs when a person’s normal breathing pattern is interrupted during sleep. The person temporarily stops breathing while they are sleeping. The gaps in breathing are called apnoeas. The word apnoea means absence of breath. Sleep apnoea sufferers stop breathing repeatedly as they sleep. Their breathing may stop anything from about 10 to over 100 times per hour of sleep and may not start again for up to a minute or more. The pauses in breathing become clinically significant if the cessation lasts for more than 10 seconds each time and occur more than 10 times every hour. In ‘primary snoring’ there are no episodes of apnoea or hypoventilation.
Obstructive sleep apnoea (OSA)
OSA is the most common form of sleep related breathing disorder and is estimated to account for over 80% of cases. It is defined as the cessation of airflow (caused by an obstruction) during sleep, preventing air from entering the lungs. Eventually, the consequent loss of breath causes the nervous system to send an alarm signal to the brain resulting in the person arousing momentarily. This comes about as a result of the increase in carbon dioxide which causes the sympathetic nervous system to release stress hormones. This reactivates the muscles that hold the throat open, the person breathes again and falls back to sleep. Typically there is a gasp or snort and their body shudders as they arouse. Usually the sufferer is totally unaware that they were momentarily jolted awake. The apnoeas prevent the sufferer from entering or spending adequate time in the deep restorative sleep stage. They also deprive the sufferer’s tissues and organs of oxygen. It’s estimated that up to 5% of adults in Western countries are likely to have undiagnosed OSA. It is more common in men, older people, and in people who are obese. It affects about 4% of middle aged men and 2% of middle aged women.
Signs and symptoms of OSA
Often, the first person to recognise the signs of OSA is the bed partner of the OSA sufferer. The signs and symptoms of OSA include:
- Loud snoring
- Noisy and laboured breathing
- Repeated short periods where breathing is interrupted by gasping or snorting
- Sudden awakenings with a sensation of gasping or choking
- Daytime sleepiness or fatigue
- Dry mouth or sore throat upon awakening
- Morning headaches
- Trouble concentrating, memory problems, forgetfulness
- Irritability or mood swings or personality changes
- Night sweats
- Gastroesophageal reflux
- Restlessness during sleep
- Sexual dysfunction, including impotence and decreased libido
- Difficulty getting up in the mornings
Risk factors for OSA
It is quite a common misconception that OSA only affects older overweight men. OSA can affect anyone regardless of age, gender, or body type. Risk factors for OSA include:
- Excess weight: Fat deposits around the upper airway may obstruct breathing. However, not everyone with OSA is overweight.
- Being male: compared to women, men have twice the risk
- Age: Middle age and older adults (40+ for men and 50+ for women).
- A large neck size: 17 inches or more for men and 16 inches or more for women.
- Nasal obstruction: due to a deviated septum, allergies, or sinus problems.
- Family history: Sleep apnoea is known to run in families.
- Smoker: Smokers are three times more likely to have OSA than are people who’ve never smoked.
- Physical features: Certain physical features can block the upper airway e.g. a narrow throat, large tonsils or adenoids, recessed chin, low-hanging soft palate, or a deviated septum.
- Use of alcohol or sedatives: These substances relax the muscles in the throat.
Possible complications of OSA
Left untreated, OSA can have life-shortening consequences. Its associations with chronic health problems include:
- It has been shown to be an independent risk factor for the development of hypertension.
- It increases the risk of stroke, regardless of whether or not the sufferer has hypertension.
- If an OSA sufferer has cardiac disease, multiple episodes of low blood oxygen can lead to sudden death from a cardiac event.
- It induces carotid artery atherosclerosis.
- It increases the risk for congestive heart failure by 2.3 times
- It is associated with cardiac arrhythmias.
- The incidence of OSA is very high in obese patients with type 2 diabetes.
- Gastroesophageal reflux symptoms may be caused or exacerbated by OSA.
- OSA sufferers are more likely to have abnormal results on liver function tests.
- OSA may worsen asthma symptoms and interfere with the effectiveness of asthma medications.
- The risk for depression rises with increasing severity of sleep apnoea.
Sleep disordered breathing in children
Sleep disordered breathing can also affect children. According to the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) approximately 10 percent of children snore regularly and about 2-4 % of children have OSA.
The AAO-HNS cite the following potential consequences of untreated sleep disordered breathing in children:
- Social: Loud snoring can become a significant social problem if a child shares a room with siblings or at sleepovers and summer camp.
- Behavior and learning: Children with SDB may become moody, inattentive, and disruptive both at home and at school. Sleep disordered breathing can also be a contributing factor to attention deficit disorders in some children.
- Enuresis: SDB can cause increased night-time urine production, which may lead to bedwetting.
- Growth: Children with SDB may not produce enough growth hormone, resulting in abnormally slow growth and development.
- Obesity: SBD may cause the body to have increased resistance to insulin or daytime fatigue with decreases in physical activity. These factors can contribute to obesity.
- Cardiovascular: OSA can be associated with an increased risk of high blood pressure or other heart and lung problems.
Since OSA is characterized by disruptions of normal breathing patterns during sleep, breathing re-education (retraining) is gaining in popularity as a treatment approach. Research has shown the effectiveness of breathing re-education (retraining) in normalising dysfunctional breathing patterns. The goal is to normalise each aspect of the breathing pattern for all situations i.e. awake, asleep, at rest, while speaking and during exercise.
A survey conducted in 2010 investigated the effectiveness of breathing re-education (using the Buteyko method) in over 11,000 sleep apnoea sufferers. The results revealed that over 95 percent of participants had improved sleep; approximately 80 percent were able to cease use of their CPAP machine or dental appliance. Symptoms such as snoring, headaches, restless legs, low concentration levels and decreased energy levels improved in the majority of participants.
American Academy of Sleep Medicine (2014) International Classification of Sleep Disorders, Third Edition: Diagnostic and Coding Manual, Westchester, Ill: American Academy of Sleep Medicine
Birch M (2010) Sleep apnoea and breathing retraining, Fitzroy (Australia): Buteyko Institute of Breathing and Health
Schraufnagel DE (ed) Breathing in America: Diseases, Progress, and Hope American Thoracic Society (2010)
Novel Insights into the Pathophysiology and Treatment of Obstructive Sleep Apnea
April 2014, Pages 2-5
Novel insights into the pathophysiology and treatment of Obstructive Sleep Apnea – Patrick Lévy
American Academy of Otolaryngology-Head and Neck Surgery website: http://www.entnet.org/content/pediatric-sleep-disordered-breathingobstructive-sleep-apnea