Definition 
Sleep apnea  is the disruption of breathing for 10 seconds or more, causing limited airflow to the lungs. 

This causes undue strain on the heart which may lead to hypertension, irregular heart rhythm, heart attacks and strokes. In addition, it causes undue strain on the brain which makes the sleep process ineffective. Ineffective sleep process causes significant mood depression, memory difficulties, trouble with concentration and productivity, as well as significant sleepiness leading to accidents if left untreated. 

Causes 
Sleep apnea may be caused by the relaxation of the muscles in the throat while a person is asleep to a point where the airway collapses and becomes obstructed. When the airway closes, a person stops breathing and awakens to open the airway.  Arousals usually only last a few seconds but disrupt a person’s sleep and makes it more difficult for a person to get into deep sleep and REM. This cycle of paused breathing occurs several times a night. Typically, the frequency of waking episodes is somewhere between 10 and 60. A person with severe OSA may have more than 100 waking episodes in a single night. 

Types of Sleep Apnea

 
1. Obstructive Sleep Apnea 
Obstructive sleep apnea is a sleep disorder caused by the obstruction of the airway.  
2. Central Sleep Apnea  
Central Sleep Apnea causes repeated disruptions in breathing because the brain temporarily stops sending signals to the muscles that control breathing. 
3. Complex Sleep Apnea  
Complex Sleep Apnea is sleep disordered breathing, secondary to simultaneous upper airway obstruction and respiratory control dysfunction. 

Risk and Predisposing Factors  

1. Excessive weight gain 
2. Age 
3. Anatomic abnormalities 
4. Enlarged tonsils and adenoids 
5. Use of alcohol and sedative drugs 
6. Smoking 
7. Nasal congestion 

Signs and Symptoms of Sleep Apnea 

1. Excessive daytime sleepiness 
2. Frequent awakening during the night 
3. Decreased memory 
4. Physical signs: loud snoring, witnessed apnea episodes, obesity 
5. Hypertension 
6. Falling asleep in stimulating and non-stimulating environments 
7. Awakening unrefreshed in the morning 
8. Headaches 
9. Poor concentration 
10. Restless sleep 

Treatment 

1. Positive airway pressure 
2. Oral appliances surgical options 
3. Weight reduction 

Possible Complications Due to OSA 

1.  Arrhythmias 
2. Heart disease 
3. High blood pressure 
4. Stroke 
5. Hypoxia 
6. Pulmonary Hypertension 
7. Mood depression 
8. Erectile Dysfunction