Daytime sleepiness and sleep habits of Australian workers.

Excessive daytime sleepiness in the general community is a newly recognized problem about which there is little standardized information. Our aim was to measure the levels of daytime sleepiness and the prevalence of excessive daytime sleepiness in a sample of Australian workers and to relate that to their self-reported sleep habits at night and to their age, sex, and obesity. Sixty-five percent of all 507 employees working during the day for a branch of an Australian corporation answered a sleep questionnaire and the Epworth sleepiness scale (ESS) anonymously. Normal sleepers, without any evidence of a sleep disorder, had ESS scores between 0 and 10, with a mean of 4.6 +/- 2.8 (standard deviation). They were clearly separated from the "sleepy" patients suffering from narcolepsy or idiopathic hypersomnia whose ESS scores were in the range 12-24, as described previously. ESS scores > 10 were taken to represent excessive daytime sleepiness, the prevalence of which was 10.9%. This was not related significantly to age (22-59 years), sex, obesity, or the use of hypnotic drugs but was related significantly but weakly to sleep-disordered breathing (frequency of snoring and apneas), the presence of insomnia, and reduced time spent in bed (insufficient sleep).