Gender differences in airway resistance during sleep

Abstract

Trinder, John, Amanda Kay, Jan Kleiman, and Judith Dunai.Gender differences in airway resistance during sleep. J. Appl. Physiol. 83(6): 1986–1997, 1997.—At the onset of non-rapid-eye-movement (NREM) sleep there is a fall in ventilation and an increase in upper airway resistance (UAR). In healthy men there is a progressive increase in UAR as NREM sleep deepens. This study compared the pattern of change in UAR and ventilation in 14 men and 14 women (aged 18–25 yr) both during sleep onset and over the NREM phase of a sleep cycle (from wakefulness to slow-wave sleep). During sleep onset, fluctuations between electroencephalographic alpha and theta activity were associated with mean alterations in inspiratory minute ventilation and UAR of between 1 and 4.5 l/min and between 0.70 and 5.0 cmH2O ⋅ l−1 ⋅ s, respectively, with no significant effect of gender on either change ( P > 0.05). During NREM sleep, however, the increment in UAR was larger in men than in women ( P < 0.01), such that the mean levels of UAR at peak flow reached during slow-wave sleep were ∼25 and 10 cmH2O ⋅ l−1 ⋅ s in men and women, respectively. We speculate that the greater increase in UAR in healthy young men may represent a gender-related susceptibility to sleep-disordered breathing that, in conjunction with other predisposing factors, may contribute to the development of obstructive sleep apnea.