Sleep duration, insomnia and longevity

摘要

Insomnia is defined as a report of difficulty falling asleep, staying asleep or non-restorative sleep associated with daytime impairment or distress [1]. Typically, it is also required that the difficulty with sleep occurs three or more times per week and be present for at least 1 month. Finally, an important qualifier for the diagnosis is that the sleep disturbance must occur despite adequate opportunity and circumstances to sleep [2]. This requirement is critical to differentiate an insomnia disorder from voluntary sleep loss (partial sleep deprivation) or from environmentally induced sleep disturbance/ sleep loss (i.e., trying to sleep in an environment conducive to non-sleep). In terms of prevalence it is estimated that the prevalence of sleep disturbance is about 30-50% of the general population. In contrast, the prevalence of insomnia is estimated as 9-14% of the adult population [3].