Sleep apnea is a disorder affecting about 18 million Americans that has the potential for serious, and even fatal complications. Persons with sleep apnea actually stop breathing for brief periods of time (usually 10-20 seconds) while asleep. The pauses in breathing can be very frequent and occur 30 times or more per hour.
The most common kind of sleep apnea is termed obstructive sleep apnea. In this case, the muscles in the throat relax to the extent that the airway is constricted or closed during inspiration (while breathing in). Breathing then stops briefly, resulting in lowered oxygen levels in the blood. The brain senses this decrease in blood oxygen and sends awakening signals so that an open airway can be restored and breathing can resume. The awakening following a pause in breathing may be so subtle that one may not remember wakening up at night. Obstructive sleep apnea occurs more commonly in men than in women and is more common in older people.
A less common form of sleep apnea is central sleep apnea, in which the brain fails to signal the muscles that control breathing. Breathing then stops and oxygen levels drop correspondingly. Awakening in central sleep apnea is usually abrupt and may be accompanied by shortness of breath.
The sudden decreases in oxygen levels that occur with sleep apnea place a burden on the cardiovascular system, which must work harder in an attempt to deliver sufficient oxygen to all tissues. This strain causes the development of high blood pressure in approximately half of those suffering from sleep apnea, and this increases the risks of stroke and heart failure.
The repeated awakening at night with sleep apnea often results in feelings of fatigue and excessive daytime sleepiness, since the ability to reach deep, restorative sleep stages is impaired. Other warning signs of sleep apnea are often noticed by bed partners and include loud snoring and making snorting or choking sounds at night. Those affected may experience awakening with brief periods of shortness of breath.
If you suspect that you (or your bed partner) suffer from sleep apnea, your doctor may refer you to a sleep laboratory for diagnosis. Treatments for sleep apnea are varied and may include physical and mechanical treatments to maintain an open airway or even surgical removal of excess tissue around the upper airway.
Source of article from here: http://www.medicinenet.com/sleep_apnea_symptoms/views.htm