Toronto, Jan 9 (IANS): A good night's sleep is linked to better performance in math and languages - subjects that are powerful predictors of later learning and academic success, says a study.

With greater "sleep efficiency", the children did better in maths and languages, but grades in science and art were not affected, the findings showed.

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 underlie the impact of sleep on academic performance, and these skills are more critical in math and languages than in other subjects," said Reut Gruber from Douglas Mental Health University Institute in Montreal.

Executive functions refer to the mental skills involved in planning, paying attention and multitasking, among others.

"Short or poor sleep is a significant risk factor for poor academic performance that is frequently ignored," Gruber said.

The researchers studied 75 healthy children aged between seven to 11 years.

The children's night time sleep was monitored by actigraphy, which uses a wristwatch-like device to evaluate sleep by measuring movements.

The findings appeared in the journal Sleep Medicine.