Infants and preschoolers who don’t get enough shut-eye at night have a greater risk of developing childhood obesity, according to a study published in Archives of Pediatrics & Adolescents Medicine and reported by HealthyDay News.

For the study, researchers looked at 1,930 children, dividing them into two groups: those ages 1 month to 59 months old (the younger group) and those ages 5 to 13 years old (the older group). Researchers gathered data in 1997 and then in 2002.

During the 2002 follow-up, researchers found that 33 percent of younger children and 36 percent of older children who didn’t get adequate nighttime sleep were either overweight or obese.

More specifically, they found that lack of sleep among the younger group in 1997 was linked to increased risk of being overweight or obese in 2002. However, lack of sleep among the older group in 1997 wasn’t associated with weight in 2002.

The findings “suggest that there is a critical window prior to age 5 years when nighttime sleep may be important for subsequent obesity status,” wrote study authors Janice F. Bell, PhD, MPH, of the University of Washington in Seattle, and Frederick J. Zimmerman, PhD, of the University of California, Los Angeles.

Although current sleep patterns among adolescents appear “to be important to weight status,” the researchers noted, “insufficient nighttime sleep among infants and preschool-aged children appears to be a lasting risk factor for subsequent obesity.”

And if you think daytime naps can make up for lost sleep, yawn, so sorry. That kind of sleeping can’t substitute for a good night’s rest and did not stop obesity, according to the study authors.

Click here to learn why obesity remains such a problem among minorities.