Trends in Self-Reported Sleep Duration among US Adults from 1985 to 2012

STUDY OBJECTIVE: The trend in sleep duration in the United States population remains uncertain. Our objective was to examine changes in sleep duration from 1985 to 2012 among US adults. DESIGN: Trend analysis. SETTING: Civilian noninstitutional population of the United States. PARTICIPANTS: 324,242 US adults aged ≥ 18 y of the National Health Interview Survey (1985, 1990, and 2004-2012). MEASUREMENTS AND RESULTS: Sleep duration was defined on the basis of the question "On average, how many hours of sleep do you get in a 24-h period?" The age-adjusted mean sleep duration was 7.40 h (standard error SE 0.01) in 1985, 7.29 h (SE 0.01) in 1990, 7.18 h (SE 0.01) in 2004, and 7.18 h (SE 0.01) in 2012 (P 2012 versus 1985 < 0.001; P trend 2004-2012 = 0.982). The age-adjusted percentage of adults sleeping ≤ 6 h was 22.3% (SE 0.3) in 1985, 24.4% (SE 0.3) in 1990, 28.6% (SE 0.3) in 2004, and 29.2% (SE 0.3) in 2012 (P 2012 versus 1985 < 0.001; P trend 2004-2012 = 0.050). In 2012, approximately 70.1 million US adults reported sleeping ≤ 6 h. CONCLUSIONS: Since 1985, age-adjusted mean sleep duration has decreased slightly and the percentage of adults sleeping ≤ 6 h increased by 31%. Since 2004, however, mean sleep duration and the percentage of adults sleeping ≤ 6 h have changed little.