When the clock strikes 9 on any given evening, 13-year-old twins Timothy and Danny Gulyn and their 11-year-old twin brothers, Christopher and Jonathan, know that it’s time for bed. Whether they are on vacation during the summer or at their Arlington home on a school night, the siblings follow a consistent routine that has them tucked-in at the same time every day.

"I am a big believer in structure and routine," said the boys’ mother, Linda M. Gulyn, Ph.D., a professor of psychology at Marymount University in Arlington. "Bedtime should be absolutely rigid, the stricter the better. We all need structure, but children need it especially."

Researchers say going to bed at a regular time can have a positive impact on a child’s behavior and overall health. In fact, a recent study of 10,000 children by University College London found that a child’s behavior improved when a consistent bedtime was established. Local childcare experts agree, saying a regular bedtime routine, such as a bath followed by reading, is an important factor in establishing a consistent lights-out time.

Kathryn Cogan, Ph.D., a Bethesda-based psychotherapist, says that a lack of adequate sleep can affect a child’s physical health. "If they don’t get enough sleep, it affects their immune system and their ability to pay attention," she said.

Child psychiatrist Dr. Bruce P. Pfeffer, of Pfeffer Psychiatric Associates in Potomac, Md., said a structured bedtime is part of what he calls "good sleep hygiene," which can impact a child’s overall wellbeing. "Often in my practice I see children with attention problems, behavior problems, irritability, who aren’t getting enough sleep," he said. "I’ve had children fall asleep in class because of sleep deprivation."

Experts say that while older children also need a good night’s sleep, the demands of school and extracurricular activities can make getting needed rest more challenging. "Failing to get adequate rest can be an extreme stress on one’s body and mind, resulting in a frantic attempt to complete academic tasks in an active rather than contemplative manner," said Michael S. Moynihan, head of the Upper School, The Heights School in Potomac, Md.

Cogan stressed that teenagers actually need a similar amount of sleep as newborns, "generally 12-14 hours of sleep at night because they are growing so fast, and their brains are growing so fast. Your brain works better and functions better when you have a regular sleep schedule."

For long-term success, experts like Pfeffer and Moynihan underscore the importance of a regular bedtime routine. It should "follow a short time of quiet reading, along with exercise," said Moynihan.

ESTABLISHING A REGULAR BEDTIME can be challenging, but not impossible. Child development experts say that a structured bedtime routine should include a few key components. "Build it into their daily routine and give them a lot of advanced warning," said Gulyn. "If I you just pluck up a kid from the middle of an activity and just say ‘Go to bed,’ that is upsetting to a child and it is not fair. They need an opportunity to make the transition psychologically. If they’re playing a game and they get a bedtime warning, they can say ‘Ok, I need to finish this game before bed.’"

When it comes to bedtime, it is important that children know what to expect, she said. "You have to make it consistent every night, even on Christmas. Give them a chance to decide how they want to spend their last half hour so they can prepare psychologically."

Pfeffer said, "It is important to establish a comfortable environment for very young children. If they start as toddlers with an established routine, they are comforted as they get older by reading a book and playing soft music in a room that is not filled with light. Bedtime should be very soothing. They take a bath, brush their teeth and put on their pajamas. A high-energy child will need more lead time to slow their motor down. "

Len Annetta, Ph.D., a professor in the College of Education and Human Development at George Mason University, said, "High energy kids need to blow off steam and tire their muscles. Routine and consistency are critical. It's not easy, but you have to shut them down at the same time every night and wake them at the same time every morning. It’s not a debate. The parent is in charge and has to stand firm on the rules. Rewarding the child for getting to bed and staying in bed … helps the child know you appreciate their effort and are proud of their accomplishment."

Kensington-based psychotherapist Karen Prince cautions, "Screen time makes it harder to fall asleep. Start the bedtime routine a minimum of an hour before the actual bedtime. It shouldn’t include television, video games or screen time of any sort."

While a regimented bedtime may sound draconian, it can actually be comforting. "Children thrive on structure and expectation," said Gulyn. "For many young children, this can be a time of uncertainty, insecurity and separation anxiety. Establishing a structured bedtime routine brings comfort to the child. If you have a structured routine and strict bedtimes, it makes it easier for a child to get to sleep and rest better throughout the night."