Long work hours usually the culprit.

• Position: Sleep Deprivation

Characteristics and behaviors associated with short sleep that could be targeted to reduce the negative health consequences have been identified by researchers at the University of Pennsylvania School of Medicine, Philadelphia, who analyzed data from a representative sample of Americans 15 years and older who participated in the American Time Use Survey between 200311.

"Intervention programs and educational campaigns can only be successful if they target the right behavior, at the right time of day, and in the right population. Time use surveys provide these crucial insights that cannot be derived from experimental or epidemiological studies," says lead author Mathias Basner, assistant professor of sleep and chronobiology. "The evidence that time spent working was the most prominent sleep thief was overwhelming. It was evident across all sociodemographic strata and no matter how we approached the question."

Individual characteristics associated with paid work, including long commute times, consistently were associated with short sleep. Short sleepers started working earlier in the morning and stopped working later at night. With every hour that work or educational activities started later in the morning, sleep time increased by...