Seventy-eight workers, drawn from a population of 1502 presumably healthy working men who were interviewed about sleep habits and sleep disorders, underwent polygraphic recordings for at least 1 night. A significant association was found between the complaint of excessive daytime sleepiness and the incidence of sleep apnea. Workers with more than 10 apneas per hour of sleep complained significantly more about loud snoring, hypermotility in sleep, and frequent headaches. They had significantly more ENT findings and hypertension.