Effect of Short Sleep Duration on Daily Activities --- United States, 2005--2008

Effect of Short Sleep Duration on Daily Activities --- United States, 2005--2008
Weekly
March 4, 2011 / 60(08);239-242

Little is known about the extent to which insufficient sleep affects the ability of U.S. adults to carry out daily activities. The National Sleep Foundation suggests that adults need 7--9 hours of sleep per night; shorter and longer sleep durations have been associated with increased morbidity and mortality (1). To assess the prevalence of short sleep duration (<7 hours on weekday or workday nights) and its perceived effect on daily activities, CDC analyzed data from the 2005--2008 National Health and Nutrition Examination Survey (NHANES). This report summarizes the results, which found that 37.1% of U.S. adults reported regularly sleeping <7 hours per night, similar to the 35.3% reporting <7 hours of sleep in a 24-hour period in another report using self-reported data (2). Short sleep duration was more common among adults aged 20--39 years (37.0%) or 40--59 years (40.3%) than among adults aged ≥60 years (32.0%), and more common among non-Hispanic blacks (53.0%) than among non-Hispanic whites (34.5%), Mexican Americans (35.2%), and persons of other races/ethnicities (41.7%). Among six sleep-related difficulties assessed, the most prevalent was not being able to concentrate on doing things, reported by 23.2% of U.S. adults. Perceived sleep-related difficulties were significantly more likely among persons reporting <7 hours of sleep than among those reporting 7--9 hours of sleep. Based on these findings, at least one third of U.S. residents do not get enough sleep on a regular basis, and this impairs their ability to perform daily tasks. Chronic sleep deprivation also has a cumulative effect on mental and physical well-being and can exacerbate chronic diseases.

This analysis was conducted using data from the last two survey cycles (2005--2006 and 2007--2008) of NHANES, a stratified, multistage probability sample of the civilian noninstitutionalized U.S. population.* A total of 10,896 respondents aged ≥20 years who completed the interviewer-administered survey questions on sleep duration were included in the sample. The response rate for the interviewed sample was 74.8%. Responses to the question "how much sleep do you usually get at night on weekdays or workdays" were grouped into categories as <7 hours, 7--9 hours, and >9 hours. Responses to six questions from the Functional Outcomes of Sleep Questionnaire (3) about sleep-related difficulties also were analyzed.†

Descriptive statistics, including population estimates, weighted prevalence, and 95% confidence intervals (CIs), were calculated to account for the complex study design. Analyses were stratified by age, sex, race/ethnicity, and education. Population estimates for sleep duration categories and each sleep-related difficulty were calculated using NHANES 4-year sample weights, which account for the differential probabilities of selection, nonresponse, and noncoverage. To compare prevalence estimates among subgroups that differed by age distribution, all estimates except age-specific estimates were adjusted by the direct method to the 2000 U.S. population. Prevalence estimates were considered significantly different if the 95% CIs did not overlap.

A short sleep duration of <7 hours on weekdays or workdays was reported by 37.1% of respondents; 60.5% reported 7--9 hours of sleep, and 2.4% reported >9 hours (Figure 1). Approximately one third of respondents reported one or more sleep-related difficulties. Among adults who reported <7 hours of sleep, the prevalence of each of the six sleep-related difficulties was higher compared with adults who reported 7--9 hours of sleep (Figure 2). For both groups, the most common sleep-related difficulty was concentrating, which was reported by 19.4% of respondents who received 7--9 hours of sleep, but 29.3% of those who received <7 hours of sleep per night.

Respondents aged 20--39 years (37.0%) or 40--59 years (40.3%) were more likely to report a short sleep duration than those aged ≥60 years (32.0%) (Table). Men (39.8%) and women (35.3%) did not differ significantly in prevalence of short sleep duration. Non-Hispanic blacks (53.0%) had the highest prevalence of short sleep duration compared with other racial/ethnic populations. Respondents who reported at least some college education (34.5%) had a lower prevalence of short sleep duration than persons with only a high school diploma (40.9%).

Among U.S. adults, 13.5% reported three or more sleep-related difficulties (Figure 1). Overall, the greatest percentage (23.2%) reported difficulty concentrating on things because they were sleepy or tired, followed by difficulty remembering things (18.2%) and difficulty working on hobbies (13.3%) (Table). Difficulty driving or taking public transportation, taking care of financial affairs, or performing employed or volunteer work because of sleepiness or tiredness was reported by 11.3%, 10.5%, and 8.6% of respondents, respectively. Adults aged ≥60 years were less likely than younger adults to report having each of the six sleep-related difficulties, and women were more likely than men to report four of the six sleep-related difficulties. Women were more likely to report most sleep-related difficulties than men, regardless of sleep duration, but both men and women reported greater difficulties if they slept <7 hours compared with 7--9 hours.

Mexican Americans were less likely to report sleep-related difficulty in performing employed or volunteer work (4.9%), taking care of financial affairs (7.5%), and working on hobbies (8.7%) than non-Hispanic whites (9.1%, 10.7%, and 13.9%, respectively) and non-Hispanic blacks (8.7%, 11.2%, and 14.1%, respectively). Non-Hispanic blacks reported a greater prevalence than other racial/ethnic populations of sleep-related difficulty in driving or taking public transportation (14.8%). Persons with at least some college education were more likely to report sleep-related difficulty performing employed or volunteer work (9.8%), but less likely to report difficulty remembering things (17.0%), compared with persons with less than a high school education (6.7% and 20.8%, respectively) (Table).

Reported by
AG Wheaton, PhD, Y Liu, MS, MPH, GS Perry, DrPH, JB Croft, PhD, Emerging Investigations and Analytic Methods Br, Div of Adult and Community Health, National Center for Chronic Disease Prevention and Health Promotion, CDC

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Effect of Short Sleep Duration on Daily Activities --- United States, 2005--2008