Survey of sleep-health and lifestyle of the elderly in Okinawa.

A total of 788 people (aged from 60 to 93 years) living in the Okinawa prefecture, renowned for the long life expectancy of its citizens, were randomly chosen as subjects. A questionnaire based on lifestyle and sleep-health was distributed. Following this, subjects were chosen in groups of nine from the good sleep-health group and then from the poor sleep-health group based on the results of the survey; their physical activities were then recorded using actigraphs for 1 week. This study suggested that lifestyle, such as exercise, walking and short naps, occupies an important position in the maintenance and improvement of sleep-health. It also verified the reliability of the sleep-health risk index and the questionnaire.