Parents know that bedtime can be one of the most challenging times of the day, particularly for young children. Babies cry and cling. Toddlers bargain, stall, and melt down when things don’t go their way. At the end of a long day, it can be tempting to let bedtime occur whenever and however it may, letting go of consistency and routine for the sake of peace, quiet, and calm.
But a regular bedtime matters. It fosters healthy, independent sleep in young children. It enables kids to get the amount of sleep they need on a nightly basis. And new research suggests that a consistent bedtime matters to children’s cognitive development, with effects that can last beyond the first few years of life.
A study out of the United Kingdom indicates that a lack of consistency at bedtime may have negative consequences for cognitive development in children by age 7. Scientists at University College London used data from the Millennium Cohort Study, a long-term, large-scale developmental study of 19,000 children in the United Kingdom. For their study on bedtime’s influence on cognitive development, researchers included data on 11,178 children, all 7 years old. They compared histories of children’s bedtimes at ages 3, 5, and 7 with test scores taken at age 7 in reading, math, and spatial awareness. Researchers found links between irregular bedtimes and lower test scores:
- Irregular bedtimes were most common at age 3. At 3 years old, 20% of children went to bed at different times nightly. Bedtimes became consistent as children aged — by age 7, more than 50% of children had regular bedtimes between 7:30 and 8:30 p.m.
- Both boys and girls with inconsistent bedtimes at age 3 had lower test scores in all three areas — reading, math, and spatial awareness — at age 7 compared to children with regular bedtimes.
- Results showed a cumulative effect of inconsistency at bedtime on learning, for both boys and girls. Girls who had irregular bedtime schedules at 3, 5, and 7 had significantly lower scores on all three test subjects. For boys, this was the case among those with irregular bedtimes at any two of the three ages.
- That both boys and girls with irregular sleep schedules at age 3 scored lower on tests at age 7 suggests that the early years of sleep may be especially important to cognitive development.
This study is significant in part because it examines the timing of sleep, not the quantity or quality of sleep. Consistency is an important aspect of healthy sleep routines at all ages, helping to strengthen circadian rhythms and ensuring sufficient time for sleep. This study suggests that consistency during these early, developmental years is critical, and can have consequences that extend beyond early childhood. We’ve seen a great deal of evidence in recent years that sleep problems in very young children are associated with negative effects on cognitive, emotional, behavioral, and social development:
- Sleep during the first few years of life may influence language skills. An international team of researchers examined the links between sleep during the first 2.5 years of life and language development up to age 5. They found that children with language delays at age 5 had poorer sleep at 6 months and 18 months than those without language delays.
- A large-scale investigation revealed that sleep-disordered breathing in children as young as 6 months predicted behavioral problems at ages 4 and 7. Problems with behavior included hyperactivity, conduct problems, difficulty with peers, and emotional difficulties. Sleep-disordered breathing is a cluster of symptoms including snoring, breathing through the mouth, and apnea. These symptoms are often thought of as adult-only problems—but that’s not the case. Children are at risk for sleep-disordered breathing, but risk factors for children appear to be different than risk factors for adults.
- Learning deficits associated with poor sleep in young children can last into adolescence. Middle-school children with low academic performance are more likely to have snored as children between the ages 2-6 than their higher-performing peers.
Infants and children up to the age of 3 require a great deal of sleep, more than 12 hours per day including naps. Sleep is critical to physical, mental, intellectual and emotional development, all of which is happening at a breathtaking pace during these early years. As this latest research indicates, in addition to sleep duration, the timing of sleep and consistency of young children’s sleep habits also make a difference in children’s healthy development. By 6 months, infants’ circadian rhythms have been established and they are physiologically capable of sleeping through the night. A sleep routine for children this age is not only possible, it’s also important for long-term development.
Developing consistent evening routines and regular bedtimes generally works best when parents start this practice early, giving children the chance to accept the nighttime schedule as a non-negotiable part of everyday life. These early-in-life sleep routines aren’t just good for peace and harmony in the household. They’re also an importance key factor in a child’s development, performance, and success for years to come.
Michael J. Breus, PhD
The Sleep Doctor™