A good night's sleep may improve the grades of schoolchildren in math and languages -- subjects that are powerful predictors of later learning and academic success.

Researchers at McGill University and the Douglas Mental Health University Institute in Montreal found that "sleep efficiency" is associated with higher academic performance in those key subjects. Sleep efficiency is a gauge of sleep quality that compares the amount of actual sleep time with the total time spent in bed.

"We believe that executive functions (the mental skills involved in planning, paying attention, and multitasking, for example) underlie the impact of sleep on academic performance, and these skills are more critical in math and languages than in other subjects," Reut Gruber, a clinical child psychologist who led the study, said in a statement. "Short or poor sleep is a significant risk factor for poor academic performance that is frequently ignored."

For the study, researchers collected data from 75 healthy children between 7 and 11 years of age. The children's nighttime sleep was monitored by actigraphy, which uses a wristwatch-like device to evaluate sleep by measuring movements. Researchers averaged the data over five nights to build the children's habitual sleep patterns and correlated the data with their report-card grades.

The findings underscore the importance of identifying sleep issues that may otherwise go unnoticed, Gruber said. It also points to a need for pediatricians to incorporate questions about sleep into routine checkups.

"I think many kids might have some sleep issues that nobody is aware of," Gruber said. "And if the pediatrician doesn't ask about it, we don't know that it's there. Regular screening for possible sleep issues is particularly important for students who exhibit difficulties in math, languages or reading."

The findings are detailed in the journal Sleep Medicine.