Daytime sleepiness is especially acute among younger adults: 44 percent of those aged 18-29 said they experience the problem at least a few days a month compared to 38 percent of 30-64 year olds, and 23 percent of those 65 and over.

Self-Described Mood Affected by Sleep
The poll results provide a clear and interesting link between the quantity and quality of respondents' sleep and their self-described overall mood. A mood and attitude score was calculated for each respondent and these scores were compared for different types of sleepers. The less respondents said they slept, the more they experienced daytime sleepiness, insomnia and other sleep problems, and, in turn, the lower their positive mood and attitude scores.

• Those who got fewer than six hours of sleep on weekdays were more likely to say they were tired than those getting more than eight hours of sleep (32% vs. 15%). They were also more likely to describe themselves as stressed (32% vs. 16%), sad (14% vs. 7%) and angry (11% vs. 4%).
• People who reported often being sleepy during the day were more likely to describe themselves as dissatisfied with life (21% vs. 7%) and angry (12% vs. 4%) compared to those who were rarely or never sleepy during the day.
• On the other hand, the less people experienced insomnia symptoms, the more likely they were to describe themselves as "full of energy," "relaxed," and "happy."

In addition to one's outlook, the poll examined the impact of insufficient sleep on behavior and ease or difficulty with tasks. Adults said when they did not get enough sleep, they were more likely to get impatient or aggravated with such common annoyances as waiting in line or sitting in traffic (64%). They also reported being more likely to make mistakes (65%) and have difficulty getting along with others (44%). A fourth of adults said they ate more than usual following nights of inadequate sleep.

More than nine out of 10 respondents agreed that not getting adequate sleep can impair their work performance (93%), put them at an increased risk for injuries (91%), and lead to health problems (90%). More than eight in 10 (85%) agreed that lack of sleep can make it difficult to get along with others, and six in 10 (62%) said it is harder to make decisions and listen carefully enough to remember what is being said.

"The new findings clearly indicate the American public understands the strong connection between their sleep, their behavior, and the quality of their daily life," said NSF's Gelula. "Yet, about one quarter of adults in this country fail to meet their own minimum sleep needs at night to be fully alert the next day."