Children and parents need a wake-up call about the importance of sleep, say medical experts who are visiting schools in Australia and New Zealand with their message.
They say too many children are not getting the good night's sleep they need to grow strong, think clearly and feel good.
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Children aged five to 12 need nine to 11 hours a night. Older children need 8.5 to 9.5 hours until the age of 18.
But research shows 20 per cent don't get the recommended amount and up to 40 per cent have poor sleep schedules.
"Undoubtedly their physical and mental health is suffering," said sleep researcher Dr Sarah Biggs.
"We're on a mission to turn this trend around."
Increasing awareness and teaching good habits would ultimately boost health and learning, said Dr Biggs, co-ordinator of the Australasian Sleep Association and Sleep Health Foundation campaign.
Volunteers from the organisations will speak to 6000 students at 23 schools on Friday, world sleep day.
Their message includes the need for children to have a regular bed time, and to limit the use of electronic devices before bed.
Devices including televisions, computers and mobile phones should be kept out of the bedroom at night.
The volunteers will also promote MWorld smartphone app that teaches children about sleep and other interesting science topics.
"Sleep is regularly ignored, even though it's a pillar of healthy living alongside sensible eating and regular exercise, said Sleep Foundation chair Professor David Hillman.
Research shows short sleep duration and poor sleep scheduling are associated with health problems such as obesity, behavioural problems and poor academic performance.
"Healthy sleep is important for physical growth, learning, positive mood, energy and daytime concentration,'' said Associate Professor Nick Antic, who heads the Australasian Sleep Association.
"sleep is not just about duration. It's about quality and having a consistent sleep routine that keeps your body clock in sync."
Symptoms of a child being sleep deprived include being overactive or moody, struggling to concentrate, falling asleep during short car trips or while watching TV, or having problems at school.
DAILY SLEEP NEEDS OF CHILDREN:
* Newborns: 12-18 hours
* Infants: 14-15 hours
* Toddlers: 12-15 hours
* Pre-schoolers: 11-13 hours
* Primary school: 9-11 hours
* Teenage: 8.5-9.5 hours
* Adults: 7-9 hours
WARNING SIGNS INDICATING LACK OF SLEEP:
* Low mood
* Poor attention
* Sugar craving
(Source: Sleep Health Foundation)