Is your toddler's body clock making bedtime a battle?


"Just one more story ... I'm thirsty ... I need to go the toilet ... I want a biscuit ... but I don't want to go to sleep!"

If the previous sentence is an accurate description of the nightly bedtime battles at your house as you try to convince your toddler it's time to head off into the land of slumber, then you are most definitely not alone.

But a new study reveals you might be fighting a losing battle trying to get your child to sleep if the bedtime you have chosen for them is out of sync with their internal body clock.

Not only that, but forcing your child to go to bed at a time that contradicts their body clock could even cause further sleep disturbances, such as insomnia, tantrums and episodes known as "curtain calls", which involve children calling out or leaving their bedroom repeatedly asking for another story, glass of water or trip to the bathroom.

Reseachers studied the sleep patterns of 14 toddlers for six days to pinpoint the time at which the hormone melatonin increased in each child. Rising melatonin levels indicate the start of a person's biological night time, and researchers found that the toddlers with later melatonin rise times took longer to fall asleep after being put to bed. Toddlers with longer intervals between the rise of their nightly melatonin levels and their bedtime fell asleep more quickly and had decreased bedtime resistance.

"There is relatively little research out there on how the physiology of toddlers may contribute to the emergence of sleep problems," Assistant Professor Monique LeBourgeois from the University of Colorado said. "Sleeping at the wrong 'biological clock' time leads to sleep difficulties, like insomnia, in adults. This study is the first to show that a poor fit between bedtimes selected by the parents of toddlers and the rise in their evening melatonin production increases their likelihood of nighttime settling difficulties.

"It's not practical to assess melatonin levels in every child. 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."

Research in adolescents and adults has shown that exposure to light in the evening can delay the timing onset of melatonin. It is yet to be shown whether restricting light during the early evening could help a toddler's melatonin levels rise earlier and make for a more peaceful bedtime for everyone.

"We believe that arming parents with knowledge about the biological clock can help them make optimal choices about their child's activities before bedtime, at bedtime, and his or her sleeping environment," LeBourgeois said. "For these toddlers, laying in bed awake for such a long time can lead to the association of bed with arousal, not sleep. This type of response may increase children's lifelong risk for insomnia over time."

Previous research has shown that a quarter of all toddlers and preschoolers have problems settling at bedtime. Children who have sleep problems in early childhood are more likely to suffer emotional and behavioral problems and learning difficulties that can last into adolescence; in addition, parents of young children with sleep problems report high levels of chronic fatigue and marital problems.