(CBS) - A study in the Journal Pediatrics finds kids who get less than the recommended amount of sleep are more likely to be cranky.
Researchers found children ages 7 to 11, who slept an average of 54 minutes less, were more temperamental.
They also found kids were able to regulate their emotions and focus in schools if they were given an extra 27 minutes of sleep.
An estimated 64 percent of school-aged children go to be later than 9 pm. experts recommend children sleep 10 to 11 hours a night.