The answers to the questions of exactly what represents a "regular" bedtime - is it OK to vary lights-out by an hour? A half an hour? - are still unknown.
There are a few possible explanations for the observations in the study. One is that children with an irregular bedtime may not be getting good quality sleep. Also, the body's circadian rhythms can be disrupted when a person doesn't have consistent sleep schedules.
Each day, as environmental stimuli influence changes in the brain, we need sleep to allow fresh learning for the day to come, according to the study. Cognitive impairment and lack of concentration are two possible consequences of limited or disrupted sleep. Given the importance of childhood development, study authors say, low-quality sleep in this critical period could have long-term health effects.
The study supports other research showing that adults also benefit from having consistent bedtimes.
"It not only helps with what's gone on the day before, but it also sets you in good stead for the day to come," Sacker said.
That makes it worth finding a consistent time to tuck in the little ones - and yourself.