A Healthy Child Needs a Healthy Brain, A Healthy Brain Needs Healthy Sleep

Here is a magnificent 2021 study performed by Professor Douglas Teti that emphasizes the importance of regularity of sufficient night sleep duration.  

It is a remarkable study because it includes measurements from four different sources (objective actigraph recordings of children’s sleep, independent observational reports from teachers and from parents, and children’s test results obtained by trained research staff) over an entire kindergarten (K) school year.  I know there’s a lot of detail here, but please read it slowly and carefully consider the impact of my ‘Sleep Advice for Parents. 

Kindergartener’s sleep was recorded early, midway, and late during the school year.  At these 3 times, teachers made assessments using well-validated measures and trained project staff tested the children.

The kindergarten children’s sleep was objectively measured at the three different time points by using actigraph wrist monitors and was collected over 8 consecutive days and analyzed three different ways:

1. What was the average duration of total sleep (sleep per 24 hours) over the week.  The emphasis is on the total sleep per 24-hours: night sleep plus day sleep 
2. What was the proportion of 24-hour periods across the week in which children had at least 10 or more hours of total sleep.  The emphasis is on how often the children were getting at least 10 or more hours of total sleep per 24-hours: night sleep plus day sleep
3. What was the proportion of nighttime sleep periods across the week in which children slept 10 hours or more.  The emphasis is on how often the children were getting 10 or more hours of sleep only during the night.

Also, three groups of children were created at a pre-K time point based on the question:  How often does your child get 10 hours of sleep at night?

A. 25% of nights, or less (“Insufficient sleep”).

B. 26-49% of nights (“Intermediate sleep”).

C. 50% of nights, or more (“Sufficient sleep”).

Conclusion: Children at pre-K with sufficient sleep at night (Group C) and children with more nights of objectively recorded 10-plus hours of night sleep during the school year (Group 3) did better in school than all other groups. Parents should pay “particular attention to the regularity of 10-plus hours of nightly child sleep established before the start of K.”

“Analysis revealed that weekly proportion of 10-plus hours of nightly sleep, particularly at pre-K, significantly and consistently predicted children’s socioemotional, learning engagement, and selected academic outcomes across the full year.  Children with more nights of 10-plus hours of pre-K sleep were rated more favorably by teachers on aggression, social competence, student-teacher relationship, classroom learning behaviors, school readiness, and ADHD behavior.   In addition, project staff rated children with more nights of 10-plus hours of pre-K sleep to be more task oriented, again, across the full K year, compared to children with less adequate sleep at pre-K.  

Children with more nights of 10-plus of pre-K sleep were also rated by the teachers as showing higher levels of academic performance across the full year, and project staff rated children with more nights of 10-plus hours of sleep at pre-K to be better at letter naming across the K year.  It appears that the regularity of children’s 10-plus hours of nightly sleep, particularly at pre-K that was the most important in predicting children’s adjustment to first-time schooling.  The current study suggests that the more consistently at least 10 hours of sleep occur during the night, the better is children’s adjustment.”  

Analyses were performed with the pre-K nighttime sleep removed and “These analyses revealed that removing pre-K sleep did not change the substantive conclusions.”  In other words, children in Group 3 with more nights of objectively recorded 10-plus hours of sleep during the school year were similar to children in Group C regarding better school adjustment.  Furthermore, night sleep duration (Group 3) appears to be more important than total sleep duration (Groups 1 and 2).

This suggests that if night sleep is short, long naps do not fully compensate even if the total (24-hour sleep) is ample.

But wait, there’s more!

1. Comparing the pre-K children with insufficient sleep (Group A) to children with sufficient sleep (Group C), those with sufficient sleep went to bed 26 minutes earlier and woke up in the morning about 52 minutes later.  So going to bed earlier allows your child to sleep in latter. SLEEP BEGETS SLEEP!  Do not assume that an earlier bedtime will make your child wake up earlier in the morning.

2. At the midway K time point, comparing the children with intermediate sleep (Group B) to children with sufficient sleep (Group C), those with sufficient sleep went to bed only about 20 minutes earlier and woke up in the morning only about 10 minutes later.  In other words, only 30 minutes of extra night sleep dramatically improves school outcomes!  Not only does sleep beget sleep, but also, SMALL AMOUNTS OF EXTRA SLEEP, OVER TIME, MAKE A BIG DIFFERENCE (Blog Post 6), especially at night, for K school adjustment.

Baby and Child Sleep Advice for Parents

 for better school adjustment

Move the bedtime earlier, maybe just 20 minutes, to get more night sleep.

Do not assume that your child will awaken earlier in the morning. 

Do not assume that long naps will compensate for short night sleep.

Additional Note

Children in Group 1 may have had some sequential nights of very little sleep and some nights of lots of sleep. The average amount of sleep over the 8 nights might appear to be adequate but there is a possible problem with this conclusion. During the sequential nights of insufficient sleep, cumulative sleepiness (Blog Posts 84 and 86) could cause a marked impairment in the child.

For more information:

Bedtime: Blog Posts 74, 123 and 129

Sleep Duration: Blog Post 137