It's after 10, and 7–year–old Tyler Flores is still awake.
Tyler's mom says they've pushed his bedtime to 930, but eventhen he still doesn't go to sleep.
She says it's taking a toll on the whole family.
Sofia Flores: "In the mornings we always get upset or mad because he's never on time. He's always tired."
A new study shows children who do not have regular bedtimes during the school week are more likely to have behavioral problems by age 7.
Yvonne Kelly, PhD, authored the study.
"Those behavioral problems include things like hyperactivity,emotional problems, conduct problems and problems with their peers," she says.
Researchers say going to bed at varying times disrupts child's developing brain and natural sleep cycles.
Some nights, Tyler's mother says he goes to bed as late as midnight.
she doesn't see behavior problems except he is sometimes distracted in school.
"He loses concentration easily," says Sofia.
Doctors recommend children Tyler's age get ten to twelve hours of sleep a night.
The behavior of the children in the study got worse the longer they went without a regular bedtime.
But children who switched to a more normal sleeping schedule saw clear improvements in their behavior.
Health experts say one sleep tip for both children and adults is no computers, televisions or mobile devices an hour before bed.