A new report suggests that napping after age 2 spoils kids’ sleep, reports the TODAY show.

“The evidence suggests that beyond the age of 2 years, when cessation of napping becomes more common, daytime sleep is associated with shorter and more disrupted night sleep,” says Karen Thorpe, a professor in development science at Queensland University of Technology in Australia. “… Daytime sleep is not a response to poor night sleep, but rather precedes poor night sleep.”