Aims: The aim of this study was to provide the first population-based descriptions of typical sleep duration and the prevalence of chronic sleep restriction and chronic sleepiness in community-dwelling Australian adults.
Methods: Ten thousand subjects randomly selected from the New South Wales electoral roll, half aged 18-24 years and the other half aged 25-64 years were posted a questionnaire asking about sleep behaviour, sleepiness and sleep disorders.
Results: Responses were received from 3300 subjects (35.6% response rate). The mean +/- standard deviation of sleep duration was 7.25 +/- 1.48 h/night during the week and 7.53 +/- 2.01 h/night in the weekends. Of the working age group, 18.4% reported sleeping less than 6.5 h/night. Chronic daytime sleepiness was present in 11.7%. Logistic modelling indicated that the independent risk factors for excessive daytime sleepiness were being older, sleeping less than 6.5 h per night during the week, getting qualitatively insufficient sleep, having at least one symptom of insomnia and lacking enthusiasm (marker of depression).
Conclusion: In New South Wales almost one-fifth of the people are chronically sleep restricted and 11.7% are chronically sleepy. Chronic sleepiness was most commonly associated with voluntarily short sleep durations and symptoms of insomnia and depression. If the experimentally observed health effects of sleep restriction also operate at a population level, this prevalence of chronic sleep restriction is likely to have a significant influence on public health in Australia.