Obstructive Sleep Apnea :

Obstructive Sleep Apnea, the more common form that occurs when throat muscles relax.

•   Excess Weight. People who are obese have four times the risk of sleep apnea that people who are a normal weight people do. Fat deposits around your upper airway may obstruct your breathing. But not everyone who has sleep apnea is overweight.
•   Neck circumference. People with thicker necks may have narrower airways. For men, the risk increases if neck circumference is 17 inches (43 centimeters) and larger. In women, the risk increases if neck circumference is 15 inches (38 centimeters) or more.
•   Being older. Sleep apnea occurs significantly more often in older adults.
•   Being male. Men are twice as likely to have sleep apnea. However, women increase their risk if they're overweight, and their risk also appears to rise after menopause.
•   A narrowed airway. You may have inherited a naturally narrow throat. Or, tonsils or adenoids may become enlarged and block the airway, particularly in children with sleep apnea.
•   Family history. If you have family members with sleep apnea, you may be at increased risk.
•   Use of alcohol, sedatives or tranquilizers. These substances relax the muscles in your throat.
•   Smoking. Smokers are three times more likely to have obstructive sleep apnea than are people who've never smoked. Smoking may increase the amount of inflammation and fluid retention in the upper airway. This risk likely drops after you quit smoking.
•   Nasal congestion. If you have difficulty breathing through your nose — whether it's from an anatomical problem or allergies — you're more likely to develop obstructive sleep apnea.