Background and objective: There is a common belief that children are not getting enough sleep and that children's total sleep time has been declining. Over the century, many authors have proposed sleep recommendations. The aim of this study was to describe historical trends in recommended and actual sleep durations for children and adolescents, and to explore the rationale of sleep recommendations.
Methods: A systematic literature review was conducted to identify recommendations for children's sleep requirements and data reporting children's actual total sleep time. For each recommendation identified, children's actual sleep time was determined by identifying studies reporting the sleep duration of children of the same age, gender, and country in the same years. Historical trends in age-adjusted recommended sleep times and trends in children's actual sleep time were calculated. A thematic analysis was conducted to determine the rationale and evidence-base for recommendations.
Results: Thirty-two sets of recommendations were located dating from 1897 to 2009. On average, age-specific recommended sleep decreased at the rate of -0.71 minute per year. This rate of decline was almost identical to the decline in the actual sleep duration of children (-0.73 minute per year). Recommended sleep was consistently ∼37 minutes greater than actual sleep, although both declined over time.
Conclusions: A lack of empirical evidence for sleep recommendations was universally acknowledged. Inadequate sleep was seen as a consequence of "modern life," associated with technologies of the time. No matter how much sleep children are getting, it has always been assumed that they need more.