Parents may be doing their child a disservice by forcing them to go to bed before they're ready.
A recent six-day study looked at when the sleep hormone melatonin was released in a group of toddlers. The team found that toddlers who had later melatonin release times were more likely to have trouble getting to sleep, a University of Colorado-Boulder news release reported.
Getting young kids to bed and asleep is a common problem for parents. Feeling sleepy at bedtime is not only influenced by pre-bedtime activities but also biology. Although studies with adults have shown that trying to sleep at a time not in sync with an individual's internal circadian clock can promote difficulties falling asleep, little is known about the timing of the circadian clock in young children," Monique K. LeBourgeois, an Assistant Professor at the Department of Integrative Physiology University of Colorado Boulder, told Headlines and Global news in an e-mail.
"Our aim was to better understand the "fit" between young kids biological clocks and the time they are put to bed by parents as it relates to them being ready for bed and sleep," she said.
Adults get to go to bed when their body feels tired; children and toddlers usually must go to bed at whatever time their parents choose for them. Sending children to bed before they are biologically prepared for sleep could cause nighttime episodes such as temper tantrums.
The researchers took saliva samples from the toddlers in order to assess their melatonin release time. The average melatonin release time was determined to be at around 7:40 p.m., which is around half an hour earlier than most parent-selected bedtimes. Most toddlers were found the fall asleep about 30 minutes after being put to bed.
It's not practical to assess melatonin levels in every child," LeBourgeois said in the news release. "But if your child is resisting bedtime or having problems falling asleep, it is likely he or she is not physiologically ready for sleep at that time."
The team found children who were put to bed before their nighty dose of melatonin was released took between 40 minutes and an hour to fall asleep.
"For these toddlers, laying in bed awake for such a long time can lead to the association of bed with arousal, not sleep," LeBourgeois said. "This type of response may increase children's lifelong risk for insomnia over time."
In the future the team plans to perform intervention studies on children with sleep problems. While it's not practical to test the melatonin release time in every child, this study shows toddlers with sleep problems could benefit from the test.
"Our findings are important in helping parents [and] physicians understand the importance of the biological clock in timing sleep for toddlers. The range of melatonin onset was wide - some kids had rises in melatonin as early as 6:30pm, while others were as late as 9:00pm. If toddlers are resisting bedtime or taking a long time to fall asleep at night, they may not be physiologically ready for sleep. Toddlers with late melatonin onsets took longer to fall asleep and were more likely to resist bedtime. Reducing light at night can shift the clock to an earlier time," LeBourgeois told HNGN.
