(HealthDay News) -- Insufficient sleep is a big problem in today's hustle-and-bustle world, even for children.

Here are red flags of too little sleep, courtesy of the National Sleep Foundation:

• Dragging oneself more than 15 minutes after waking up.
• Sleeping at least two hours extra on weekends and holidays than on weekdays.
• Falling asleep in the car or during activities where you should be staying awake.
• Acting grumpy, irritable or hyperactive.