Sometimes the bedtime battle can make a mama feel like it would be easier to just let the kids fall asleep whenever they want, but there are huge benefits to a consistent bedtime routine, and one big drawback to letting kids head to bed whenever.

A study out of the UK looked at the bedtime habits of 10,000 kids when they were between 3 and 7 years old and found that kids with non-regular bedtimes had more behavioral difficulties than those with a predictable bedtime routine.

The study was published in 2013 in the journal Pediatrics, and found that about 20% of parents said their 3-year-old did not have a consistent bedtime. The researchers found that kids who did not have a set bedtime scored higher when it comes to things like unhappiness, being inconsiderate and fighting. Those scores came not only from parent reports, but also from teachers of school-age kids, who rated the behavior of kids without regular bedtimes as more problematic.

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According to the study’s lead researcher, Yvonne Kelly, putting kids to bed at 8:00 p.m. one night and 10:00 p.m. the next results in a kind of “social jet lag,” even if they’re getting the same hours of sleep.

“Without ever getting on a plane, a child’s bodily systems get shuffled through different time zones, and their circadian rhythms and hormonal systems take a hit as a result,” Kelly explains in a 2017 article she authored for The Conversation.

In that article she explains that her team “did find an important piece of good news, too: those negative effects on behavior appeared to be reversible.”

How much sleep does my child need? Chart shows hours of sleep needed by child's age

When kids in the study switched from having irregular bedtimes to having a regular bedtime, there were measurable improvements in their behavior. “This shows that it’s never too late to help children back onto a positive path, and a small change could make a big difference to how well they get on,” she explains.

In a follow-up study published in 2017 the researchers found that irregular bedtimes don’t just impact behavior, but can also put kids at risk for obesity and low-self esteem, and tank their math scores. Regular bedtimes, on the other hand, can have a positive impact on a kid’s development, health and behavior.

So the next time you’re tempted to let bedtime slide, remember that by being strict with bedtime you’re not only protecting your own sleep and self-care time, but also protecting your child’s circadian rhythms and happy tomorrow.

A version of this story was originally published on March 18, 2019. It has been updated by Motherly editors.