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Sleep Apnea Explained

Do you have a snoring problem? Do you feel listless and sleepy during the day? There is a chance you may be suffering from Obstructive Sleep Apnea (OSA).

What is Sleep Apnea?

Sleep apnea is a potentially serious disorder that causes the sufferer’s breathing to be interrupted by repeated pauses during sleep. An apnea, which literally translates as “without breath”, refers to completely obstructed breathing. In clinical terms, it is the condition that causes the sufferer’s airflow to be reduced for about 10 seconds or more.

There are two types of sleep apnea; namely Obstructive Sleep Apnea (OSA) and Central Sleep Apnea (CSA). OSA is caused by complete or partial blockage of the airways during sleep. CSA is usually caused by medical conditions that hinder the brain’s ability to signal the muscles responsible for controlling breathing. Based on overnight sleep study (polysomnography) results, OSA is far and away the more common type – accounting for 90 – 96% of all apneas.

It is important to note that both OSA and CSA can cause serious health issues. Untreated sleep apnea can lead to serious medical and lifestyle problems including diabetes, high blood pressure, increased risk of stroke, daytime fatigue or a lack of concentration in school or at work.

Causes and symptoms

Most people would associate sleep apnea with snoring. In reality, OSA has many well-documented signs and symptoms, many of which are direct or indirect consequences of disrupted sleep.

The sleep deprivation is caused by the breathing interruptions that occur throughout the night. An adult requires about 7-8 hours of sleep per night, a quarter of which time is spent in the deepest phase of sleep. It occurs approximately once every minute, which effectively robs the sufferer of the adequate rest he or she needs in order to function properly the next day. As such, the signs and symptoms may be classified into two categories: Those that occur as a result of the condition, usually during sleep, and others that are knock-on effects of these nocturnal symptoms, or if you prefer, the daytime symptoms.


Nocturnal symptoms and effects

Snoring: Usually the first and most telling sign. Can be persistent and loud, hence causing annoyance to others, especially a spouse or partner.
Choking/ gasping for air: Follows after pauses in breathing during sleep. A common OSA symptom if witnessed repeatedly at night.
Wake up to urinate more than usual.

Daytime symptoms and effects

Excessive sleepiness: Due to insufficient rest.
Dry mouth/ sore throat: Usually experienced in the morning when you wake up. Caused by sufferers’ tendency to breathe through mouth during sleep.
Morning headaches
Prone to irritation and mood swings: May be attributed to fatigue.
Lack of concentration
Memory loss
Bed-wetting: Affects mostly children.

Causes of sleep apnea

As mentioned, anyone can have sleep apnea. However, a person might have certain physical attributes, medical conditions or natural dispositions that can contribute to either obstructive sleep apnea or central sleep apnea.

The risk factors for obstructive sleep apnea are:

Males over the age of 65
Family history of sleep apnea sufferers
Certain facial bone shape/ muscle size: E.g. Receding chin, enlarged nostrils.
Allergies and medical conditions: especially those that cause nasal blockages.
Certain illnesses: Central sleep apnoea is normally associated with serious medical conditions like stroke, heart disease or neurological condition.

Types of Sleep Apnea

The two types of sleep apnea are: Obstructive Sleep Apnea (OSA) and Central Sleep Apnea (CSA).
Obstructive Sleep Apnea (OSA)

When we sleep, the muscles in our bodies become more relaxed – including those muscles that help to keep our throats open so that air can flow into our lungs. Obstructive sleep apnea occurs when tissues and muscles in the upper airway collapse resulting in a narrowed or partially blocked air passage. This contributes to pauses in breathing, which is called an apnea. Common tell-tale signs of an OSA sufferer is someone who snores loudly or repeatedly chokes and gasps while sleeping.

Obstructive sleep apnea is the most common form of sleep apnea that affects about 90%-96% of patients with breathing disorders. The Apnea Hypopnoea Index (AHI) is the most widely acknowledged measurement of OSA. Derived from an overnight sleep study, the AHI measures the extent of OSA; scores of > 5 indicates the presence of OSA and > 30 signalling a severe case.

According to estimates derived from AHI readings, obstructive sleep apnea occurs in approximately 24% of middle-aged males and 9% of middle-aged females. These estimates are consistent with a 2010 report by the Australian Institute of Health and Welfare that finds the sleeping disorder affecting around 26% of male Australians between ages 40 – 65. It is more likely to affect middle-aged males, with higher incidence rates amongst smokers and frequent alcohol consumers. Loud snoring is a common symptom of OSA sufferers.
Central Sleep Apnea (CSA)

Central Sleep Apnea occurs when the patient’s brain fails to signal the muscles to breathe, which often result in longer lasting and more frequent apneas (breathing pauses) as compared to OSA. It affects about 10% of people with breathing problems. Unlike OSA, patients with CSA do not suffer from a blocked airway. The body isn’t making any attempts to breathe during the pauses. The breathing stops momentarily until there is another effort to breathe again. There are many possible reasons for CSA: Weakness of muscles that enable lungs to expand and contract; stiffened lungs; neuromuscular disorders, etc. CSA not only results in sleep deprivation but also causes your body to retain carbon dioxide, leading to morning headaches and other symptoms.

How is OSA diagnosed?

OSA diagnosis primarily takes the form of a sleep study – also known as a polysomnography. A sleep physician will administer the polysomnography, during which multiple physiological monitors will be attached to the patient’s body while several electrodes are pasted to his or her head. While the monitors record the nocturnal breathing patterns as well as brain and physical activity, the electrodes measure the brain’s electrical activity via an electroencephalogram (EEG). The study shows the brain activity at different stages of sleep and whether the patient is aroused during these stages thus losing adequate rest. When the number of arousal events recorded by the polysomnography exceeds certain pre-determined markers, it would indicate either the presence or severity of the sleeping disorder.

Risk factors and effects

Like any other respiratory condition, you should seek early treatment if you have been diagnosed with sleep apnea. Delayed treatment may aggravate the condition with serious health implications. Besides those effects mentioned above that serve as symptoms of the condition, there are other long-term effects associated with sleep apnea. The following are serious consequences of sleep apnea, many of which can be attributed to the long-term effects of oxygen depletion as caused by the breathing disorder.

High blood pressure: 45% of OSA patients that do not have high blood pressure will develop it within 4 years if their condition is untreated.
Stroke: Risk increases by 1.5 times.
Heart failure: Risk increases by 2.3 times.
Pre-diabetes and diabetes
Heart rhythm disturbances
Cognitive impairment
Impaired mental processes
Death: OSA can increase the risk of sudden death, which may impact both the patient and their loved ones, for example, if they are operating a vehicle when the sudden death occurs.


Dental Appliances
The Mandibular Advancement Splint/ Device (MAS/ MAD) is a frequently recommended oral appliance solution that works by repositioning the mandible – the largest and lowest facial bone that holds the teeth in place – in such a way that prevents your tongue from obstructing your airway during sleep.

It is very important to get your oral appliance supplied and fitted by a dentist who specialises in sleep apnea. It is also recommended that you visit the dentist regularly during the treatment process. Not only will the dental practitioner be able to deal with any unforeseen dental problems that may occur during the treatment phases, the clinician is also in the best position to periodically adjust your device to fit better.

Continuous Positive Airway Pressure (CPAP)
The CPAP machine is a portable unit with an attached face/nasal mask connected via tubing. The machine delivers gentle streams of pressurised air through the mask to hold the palate, nose and throat tissues open. The mask is worn with a bit of suction to the face to avoid air leakage. CPAP is not easy to use for some people, as not everyone can tolerate sleeping with the face mask and constant blowing of pressurised air through one’s nostrils and throat throughout the night.

It has been difficult finding appropriate medication to treat obstructive sleep apnea simply because the narrowing of the airway is due to anatomic reasons, rather than medical ones. That said, many medications have been tested and used for specific cases with varying results. These include nasal steroid sprays, topical nasal decongestants, thyroid replacement therapy (for those whose OSA is caused by hypothyroidism) and diet medications.

Many types of surgery, usually performed on an outpatient basis – are available to help people with sleep apnea. They are typically recommended for patients who have difficulty coping with conservative treatments like CPAP therapy. Somnoplasty is a minimally invasive procedure that administers low-power radio frequency (RF) energy to tighten the soft palate at the back of the throat in order to enlarge the airway. The upper airway stimulator involves a procedure that places a tiny pulse generator – with a device called Inspire – in the upper chest to stimulate the nerves that control airway muscles. Other types of surgery include the mandibular/maxillary advancement surgery and nasal surgery, both of which are intricate procedures reserved for patients with severe sleep apnea problems.

Home Treatment
Weight loss regimes have become an integral facet of many sleep apnea treatment programs. Since obesity is one of the main causes of sleep apnea, sleep physicians often recommend nutritional diet and exercise as part of a holistic treatment. Other lifestyle changes include: Limiting the intake of tobacco (quit smoking), alcohol and sleeping pills; change of sleeping position, and getting plenty of sleep.

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