[Gender difference in the respiratory functions of the upper airway]

Gender differences could exist in the respiratory functions of the upper airway, especially when they relate to sleep and possibly sleep apnea. Particular attention should be given to factors related to upper airway patency, considering the gender difference of anesthesia. The pharyngeal airway is open during wakefulness but occludes during sleep implicating a neural component dependent upon state of vigilance, although anatomical upper airway narrowing in the genesis of airway occlusion during sleep plays an important role. Respiratory disturbances, including sleep apnea syndromes, are less common in women than men until after menopause. Particularly marked is the male predominance among patients with obesity hypoventilation syndrome. While obesity increases the risk of developing sleep-disordered breathing in both sexes, women with sleep apnea syndromes are more massively obese than their male counterparts. Several factors may contribute to the protection in herento premenopausal women, including the presence of female hormones, the absence of male hormones, and the effects of gender or age unrelated to sex hormones. These factors, in turn, appear to influence airway patency and ventilatory control.