Children’s sleep: Never enough?

Over the years, children’s sleep has consistently fallen short of recommendations, although it has never been established exactly how many hours children of different ages should be sleeping. One new study shows that actual sleep time is decreasing, whereas another suggests that current guidelines may not accurately reflect the amount of sleep children need for optimal school performance.

Insufficient sleep has been linked to a spectrum of physical and psychological problems, and for more than 100 years, attempts have been made to define the appropriate amount of sleep for children and adolescents. A review of the literature published between 1897 and 2009 identified 32 sets of sleep recommendations for children, yielding 360 age-specific recommendations. Matching data on actual sleep were available for 173 of the 360 recommended sleep durations.

Recommended sleep duration decreased over time by an average of –0.71 minutes per year, which was almost identical to the decline in actual sleep time of –0.73 minutes per year. Although both fell over time, recommended sleep was consistently about 37 minutes greater than actual sleep. Another consistency in the various studies is that researchers suggest that overstimulation by “modern life,” whether electric light in the early 1900s or electronic media today, is a reason why children are not getting enough sleep. Also, researchers universally acknowledge the lack of empirical evidence for sleep recommendations.

In another study, researchers used nationally representative data to assess the relationship between sleep and primary and secondary school students’ performance on standardized tests. They found a significant effect of sleep on math and reading test scores, with the right amount of sleep for optimal performance decreasing with age from 9 to 9.5 hours for 10-year-olds; 8 to 8.5 hours for 12-year-olds; and 7 hours for 16-year-olds. These estimates are lower than the 9.25 hours typically recommended in sleep guidelines, the researchers note.

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