If you have not already done so, please read Blog Posts 1 through 5 that describe how sleep is important and beneficial. I will post specific information for parents and children based on my book, “Healthy Sleep Habits, Happy Child.” Please do not be put off by my book’s length. This is a reference book. Read only the topic of interest to you.
Late bedtimes in preschool children are usually associated with less night sleep but in some pre-school children, they may have late wake-up times so night sleep duration is not much affected.
Late bedtimes in preschool children are usually associated with less night sleep and longer naps, but the longer naps do not fully compensate so total 24 hour sleep duration is usually less.
Late bedtimes that occur after the onset of the biological circadian onset of sleepiness (that is, after the time when the brain actually wants to go to sleep) might be harmful, independently of sleep duration.
A 2024 study of a diverse national birth cohort of 1,500 urban children from 20 cities with populations greater than 200,000 showed that:
Later bedtimes at age 5 was associated with more marijuana use at age 15.
Later bedtimes at age 15 was associated with more marijuana use.
A 2024 study of over 5,000 children categorized them, at ages 4 years, based on bedtimes and wake times:
At age 7 years, the children’s dietary patterns were described as ‘Healthier’, ‘Energy-Dense Foods’, and ‘Snacking’.
“Children who had a late sleep, independently of the time of waking up, had higher odds of following the ‘Energy Dense Food’ pattern, compared with the ‘Healthier’… a late sleep or late wake were associated with a lower diet quality, compared to the group ‘Early Sleep-Early Wake’, and independently of nap behaviour…In conclusion, preschoolers with late bedtimes or wake-up times have worse dietary patterns and poorer diet quality at the age of 7 years, which seems to be independent of sleep duration.”
A 2024 study showed that a behavioral intervention of moving the bedtime earlier caused a beneficial effect on weight status, in children 8-11 years-old. Objective measurements of sleep showed that the earlier bedtime was a key factor, not sleep duration.
Blog Post 212 discusses the importance of early bedtimes and how a bedtime only 6-12 minutes earlier, over time, can make a big difference!
