Gender differences in airway resistance during sleep.
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 approximately 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.
Trinder
J
J
School of Behavioural Science, University of Melbourne, Parkville, Victoria 3052, Australia.
Kay
A
A
Kleiman
J
J
Dunai
J
J
D000293:Adolescent; D000328:Adult; D000403:Airway Resistance / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D015656:Respiratory Mechanics / Q000502:physiology; D012727:Sex Characteristics; D012890:Sleep / Q000502:physiology*