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. 2013 Apr 1;36(4):527–534. doi: 10.5665/sleep.2538

Figure 4.

Figure 4

Mean sleep durations in adolescents age 9-18 y in Europe (Belgium, Finland, France, Germany, Hungary, the Netherlands, Norway, Spain, Sweden, Switzerland, the United Kingdom), the United States and Asia (China, India, Japan, Korea) (from Olds et al.76). The solid horizontal line and gray area represent the National Sleep Foundation (NSF) guidelines,46,47 the dotted line the National Heart, Lung and Blood Institute (NHLBI) guidelines,45 and the straight horizontal line represents guidelines from Harvard.49 As shown, the NSF,46,47 which cites the study by Carskadon et al.,37 recommend children age 9-18 y get 8.5-9.25 h of sleep; the NHLBI,45 which does not provide any references, recommend 10 h of sleep; and Harvard,49 who cite Ferber,35 Dijk et al.,34 and Ohayon et al.,36 recommends 9 h of sleep.