One of a parent’s biggest worries from Day 1 is exactly how much sleep their child is getting — and whether it’s enough. From the time they’re infants to when they’re teens (and sometimes even when they’re adults), it’s easy to worry about the quantity and quality of your kids’ sleep, since it’s been linked to everything from brain development to growth to behavior to mental health to academic performance.

But what if we aren’t worrying about the things about sleep that affect our kids the most? A new study, published this month in the Journal of Developmental and Behavioral Pediatrics, found that one aspect of kid sleep that might be more important than we thought is consistent bedtime and bedtime routine.

For the study — part of the Penn State Intervention Nurses Start Infants Growing on Healthy Trajectories (INSIGHT) study — researchers looked at what happened when 143 6-year-old kids were given a stressful problem to work through and a group activity to complete. Some of the participants had a consistent bedtime routine and others did not.

What they found was surprising. For seven nights before the tests, kids wore a smartwatch that measured their bedtime, their waking time, the quality of their sleep, and the total amount of sleep that the kid got. Kids who had a consistent bedtime performed best in the tests — one of which had the kids trying to unlock a toy box with a set of keys that did not work and one of which had the children decorate a picture frame with their parents.

If kids went to sleep around the same time each night, they were less frustrated during the first test and did not display anti-social behavior in the cooperative test (like talking back, yelling, or refusing to participate). Even more interestingly, the more their bedtimes varied, the worse they did.

“Children who had consistent bedtimes were generally able to regulate their behavior and emotions,” study co-author Adwoa Dadzie told Science Daily. “On the other hand, children whose bedtimes and sleep times were all over the place showed more impulsivity and less control.”

Children who went to bed within a 20-minute window, for example, were significantly more able to self-regulate their emotions than a kid who had a two-hour window.

Perhaps even more interesting is that the kid’s length and quality of sleep did not significantly impact their behavior during the tests.

“It’s amazing,” study co-author Orfeu Buxton told Science Daily. “Parenting matters. When parents establish clear structures and respond to their child’s needs appropriately, children have better outcomes in… behavior — even years later.”

This is not the first time that a study has found that consistent bedtime might matter more than other aspects of sleep hygiene. In 2023, the journal Sleep reported that a study of 60,000 people in the UK found that going to bed at a regular time was had a greater overall health impact than getting eight hours of sleep per night. Specifically, people in the top 20 percent of sleep regularity had a lower all-cause mortality risk than those in the bottom 20 percent who had erratic sleep patterns.

And, again in the study, sleep duration didn’t reduce the risk of mortality. There might be a lesson here for people of all ages!

Parenting is super-hard, and having a consistent bedtime every single night is nearly impossible, but working toward getting everyone in the house asleep at a consistent time (including you!) could go a long way toward increasing your family’s health and wellbeing.