Sex differences in sleep

There are sex differences across many aspects of sleep behavior, perception, and physiology, sleep disorder presentation, and in the consequences of sleep loss. Women report more sleep problems and a poorer sleep quality than men, starting in adolescence and persisting across the lifespan. This poorer self-reported sleep quality is reflected in greater sleep complaints and a higher prevalence of insomnia disorder in women, which could be related in part to their increased likelihood to experience depression and anxiety symptoms, effects of reproductive life cycle events (e.g., insomnia linked to the menopausal transition), circadian factors, a greater sleep need that is not being met, and social factors. In contrast to self-report, polysomnographic (PSG) recordings show that women have better sleep than men across a wide age range, suggesting that objective and subjective assessments tap into different constructs of sleep. Starting in adolescence, women have less NREM (N1 sleep), fewer awakenings, and more slow wave sleep (N3 sleep) than men. Analyses of the sleep electroencephalograph (EEG) also indicate sex differences. Women have more absolute EEG power across a wide frequency range including slow wave and sigma (spindle) activity, and longer spindle duration and higher spindle and slow wave amplitude than men. Differences in amplitude may be due, in part, to neuroanatomical differences. Women show a more pronounced response to sleep deprivation and diverge from men in the consequences of sleep loss for functioning of multiple systems, including the cardiovascular system, reflecting sex differences in mechanistic pathways for the impact of sleep loss as well as in severity of sleep loss effects. Sexual differentiation of sleep may be instigated in part through the organizational and activational effects of sex steroids. In addition to insomnia, there are also sex differences in the prevalence of other sleep disorders, like obstructive sleep apnea, which is more prevalent in men. Sex, therefore, is an important factor in determining sleep behavior, sleep architecture and sleep disorder prevalence and presentation.