The importance of sleep in maintaining good health and quality of life is well recognized. Despite evidence of the health implications of insufficient sleep, a large number of Americans do not routinely get optimal hours of sleep (1
). It is estimated that 70 million Americans are affected by chronic sleep loss or sleep disorders (1
). National surveillance of adult sleep practices was first undertaken in the National Health Interview Survey (NHIS) in 1977 in response to the public health community’s increased focus on healthy behaviors for promoting health and preventing disease (2
This report provides a national perspective on the association between sleep and selected health risk behaviors using data from the 2004-2006 NHIS. Prevalence of cigarette smoking, alcohol use, leisure-time physical inactivity, and obesity are examined by usual sleep duration among a nationally representative sample of U.S. adults, stratified by sex, age, and race/ethnicity. The goal is to identify variations in prevalence of these health risk behaviors by usual sleep duration and to identify subgroups for which these associations may be particularly noteworthy. Direction of causality cannot be determined with cross-sectional survey data. However, identifying health risk behaviors among adults with varying sleep durations can provide useful information on possible clustering of behaviors that are known to be associated with unfavorable health outcomes.
Prevalence of sleep
During the period 2004-2006, about 6 in 10 U.S. adults (63%) usually slept 7 to 8 hours in a 24-hour period. About 1 in 10 adults (8%) slept less than 6 hours, 2 in 10 slept 6 hours (21%), and about 1 in 10 (9%) slept 9 or more hours. Rates of cigarette smoking, alcohol use, leisure-time physical activity, and obesity varied by usual hours of sleep across most population subgroups studied. Sample size is limited for some subgroups. Estimates should be interpreted in conjunction with reported standard errors.
Sleep and smoking
Overall, in 2004-2006, about 21% of U.S. adults were current cigarette smokers. Rates varied according to usual hours of sleep, and were lowest among adults who slept 7 to 8 hours (18%) and higher among adults who slept less than 6 hours (31%) or 9 hours or more (26%). For both men and women, smoking prevalence was substantially higher among those who slept less than 6 hours than among men and women who slept 7 to 8 hours. Of the age groups studied, the association between hours of sleep and cigarette smoking was most notable for younger adults. Adults aged 18-44 years who slept less than 6 hours were more likely to be current smokers (38%) than adults in the same age group who slept 7 to 8 hours (21%). Variations by race and ethnicity were also found. Non-Hispanic white adults who slept less than 6 hours were more likely to be current smokers (34%) than non-Hispanic white adults who slept 7 to 8 hours (20%). Results for Hispanic adults also revealed higher smoking prevalence among those who slept less than 6 hours (19%) compared with those who slept 7 to 8 hours (13%) but the difference was smaller than for non-Hispanic white adults.
Sleep and alcohol use
Alcohol use also varied by usual hours of sleep, although to a lesser extent than observed for cigarette smoking. Overall, about one in five adults (20%) had had five or more drinks in 1 day in the past year. Prevalence of this behavior was slightly higher among adults who slept 6 hours or less (22%) than among adults who slept 7 to 8 hours (19%) or 9 hours or more (19%). The association between having five or more drinks in 1 day and hours of sleep was most notable for men and for younger adults. Men who slept less than 6 hours were more likely to have had five or more drinks in 1 day (31%) than men who slept 7 to 8 hours (27%). Similarly, adults aged 18-44 years who slept less than 6 hours were more likely to have had five or more drinks in 1 day (33%) than adults in the same age group who slept 7 to 8 hours (26%) or 9 hours or more (26%). Sleep was unrelated to having five or more drinks in 1 day among adults aged 45 years and over for whom prevalence of consumption of this amount of alcohol was considerably lower.
Sleep and physical inactivity
Overall, about 4 in 10 adults were physically inactive in their leisure time. Rates of leisure-time physical inactivity were lowest among adults who slept 6 hours (39%) or 7 to 8 hours (38%). For both men and women and across all age groups studied, adults who slept less than 6 hours and those who slept 9 hours or more had higher rates of physical inactivity than adults who slept 7 to 8 hours. The same pattern was observed among non-Hispanic white adults. Rates of leisure-time physical inactivity were higher among non-Hispanic white adults who slept less than 6 hours (42%) or 9 hours or more (45%) compared with non-Hispanic white adults who slept 7-8 hours (33%). Non-Hispanic black adults who usually slept 9 hours or more (58%) had the highest rates of leisure-time physical inactivity and rates were lower among non-Hispanic black adults who slept 7 to 8 hours (52%), 6 hours (46%), or less than 6 hours (49%).
Sleep and obesity
Overall, about one in four adults were obese (25%), based on self-reported height and weight. Adults who slept less than 6 hours had the highest rate of obesity (33%) and adults who slept 7 to 8 hours had the lowest (22%). This pattern was found for both men and women and across all age groups and most race/ethnicity groups studied. The association between sleep and obesity was less striking among adults aged 65 years and over than among younger adults.
The findings in this report, based on a survey of a representative sample of U.S. adults, offer a national perspective on the association between sleep practices and other health-related behaviors in the U.S. adult population. The findings presented here suggest that U.S. adults who usually slept less than 6 hours were more likely than adults who slept 7 to 8 hours to engage in certain health risk behaviors (i.e., cigarette smoking, having five or more drinks in a day, engaging in no leisure-time physical activity, and being obese). In many cases, adults who usually slept 9 hours or more were also at increased risk of engaging in these unhealthy behaviors. The associations between sleep and other behaviors are complex, and the directions of causality cannot be determined with the cross-sectional data used in this analysis. Additional analyses are needed to identify the causal directions of these relationships, as well as to identify factors, such as poverty or educational attainment, that may influence sleep and its associated factors. Despite these limitations, the findings presented here provide important information about the potential relevance of discussing health risk behaviors such as smoking, alcohol use, physical inactivity, and obesity with patients who seek medical advice for sleep concerns.
1. National Heart, Lung, and Blood Institute. Your guide to healthy sleep. National Institutes of Health. NIH Pub No. 06-5271. Department of Health and Human Services. November 2005.
2. Schoenborn CA, Cohen BH. Trends in smoking, alcohol consumption, and other health practices among U.S. adults, 1977 and 1983. Advance data from vital and health Statistics no 118. Hyattsville, MD. National Center for Health Statistics. June 30, 1986.
By Charlotte A. Schoenborn, M.P.H., and Patricia F. Adams
Division of Health Interview Statistics
For the complete report visit the Web site of the National Center for Health Statistics.