Children who do not get adequate sleep have 1.5% shorter telomeres for each hour less that they sleep per night. Telomeres are caps at the end of chromosomes that protect DNA from damage but they get shorter every year and thus are a biomarker for aging.

Many environmental factors have been shown to either accelerate or slow telomere shortening. Lack of sleep has been shown to accelerate telomere shortening in several studies in adults but this is the first study looking at telomere length in children. According to the author of this study, the current recommendation is for such children to get between 9 and 11 hours of sleep.