Once normal breathing is restored, the person falls asleep only to repeat the cycle throughout the 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. The primary risk factor for OSA is excessive weight gain. The accumulation of fat on the sides of the upper airway causes it to become narrow and predisposed to closure when the muscles relax.
Age is another prominent risk factor.
Loss of muscle mass is a common consequence of the aging process. If muscle mass decreases in the airway, it may be replaced with fat, leaving the airway narrow and soft. Male hormones can cause structural changes in the upper airway. The signs and symptoms of OSA result from disruption of the normal sleep architecture. The frequent arousals and the inability to achieve or maintain the deeper stages of sleep can lead to excessive daytime sleepiness, nonrestorative sleep, automobile accidents, personality changes, decreased memory, impotence, and depression.