Sleep Apnea
Sleep Apnea is one of the sleep respiratory disorder. It’s severity is classified by the frequencies of pauses of breathing. Base on the causes of apnea, sleep apnea consists of 3 main categories
- Obstructive Sleep Apnea
- Central Sleep Apnea
- Mixed/ Complex Sleep Apnea
Obstructive Sleep Apnea
The most common type of sleep apnea, up to 84% of cases fall into this category.。睡It is caused by physical blockage of upper airway, including excess fat tissue, anlarged lymphoid tissues, structural reason, etc. Low muscle tone during sleep (esp. deep sleep) will give rise to blockage and thus causes breathing difficulties.

- Normal upper airway (left)and physically blocked upper airway (right)click to zoom
Central Sleep Apnea
Occurs when upper airway is not blocked but nervous system fails to signal muscles to breathe. Thus causes pauses in breathing. Less than 1% cases belong to central sleep apnea, mostly patients who had stroke or brain damage(s) before.
Mixed Sleep Apnea
Mixed Sleep Apnea occurs when someone has both obstructive and central sleep apnea. About 15% cases belong to mixed sleep apnea.
FAQ’s
Sleep apnea patients often suffer from following symptoms when not under proper treatment:
- Snoring
- Nocturia
- Pauses of breathing along with arousal
- Fatigue
- Headache
- Reduced concentration
- Hypertension, etc.
Please consult your physician if you suspect you are one of the sleep apnea patients. Physician may arrange sleep test/ sleep study to further diagnose if any sleep disorder.
Untreated sleep apnea can highly increase risks of diseases and symptoms such as:
- Hyertension
- Stroke
- Coronary heart disease & heart failure
- Diabetes
- Glaucoma
- Depression
- Obesity
- Chronic fatigue
- Headache
According to research, following risk factors had been found to highly related to sleep apnea:
- Middle aged or elderly
- Male (about a fold more probable than female)
- Over-weighted, one of the major factor for obstructive sleep apnea
- Thick neck
- Family history of sleep apnea
- Smoker or drinker
Technically, sleep apnea consists of several types of events including:
ObstructiveCentralMixed/ ComplexHypopneaRERA (Respiratory effort related arousal)when these events occurs more than 5 times/hour, patient will be diagnosed to have sleep apnea.
Severity of sleep apnea is identified according to number of times of apnea events per hour during sleep. The number is also called Respiratory Disturbance Index.
5-15 times/ hour = Mild
15-30 times/ hour = Moderate
30 times or more/ hour =Severe