THE technology age has robbed young Australians of half an hour of solid sleep a night in the past two decades, a major survey has found.
A report on the sleeping patterns of 28,000 children and teenagers has confirmed that younger people are sleeping much less than they used to on school days, and are building up a chronic "debt" that has to be slept off on weekends.
The study found showed kids' wake-up time had barely changed - almost all rise within 15 minutes of 7am - but they were going to bed later, mainly thanks to video games, internet and television.
Sleep researcher Professor Timothy Olds, from the School of Health Sciences at the University of South Australia, compared two surveys of Adelaide children aged 10-13 to analyse sleep changes between 1985 and 2004.
"The decline was striking," Prof Olds said.
"There was a 30-minute drop in sleep on school days, which is a minute-and-a-half less each year - very, very marked."
He said a drop had been observed in adults over the past hundred years, mainly due to the advent of electric lights, caffeine and more recent technological advances.
However, only one study, from Switzerland, had ever analysed this in younger people.
They were watching late shows more than ever, as well as live broadcasts of international sport like the US Open or Tour de France now possible with 24-hour global TV.
The research will be presented at an international sleep conference, worldsleep07, starting in Cairns on Sunday, which showcases the latest science on snoring, insomnia, sleeping tablets, dreaming and other sleep issues.
Older teenagers seemed to have more homework pressures, more part-time work on weekdays and were socialising more, Prof Olds said.
And a lack of sleep on weekdays seemed to be fuelling bigger sleep-ins on weekends, creating "lopsided" patterns which researchers said caused havoc with circadian rhythms, or body clock.
"By the time kids get to 17-18 they're getting eight hours sleep on school days and 10 hours on non-school days, when they should really be getting something in between nightly," he said.
"This pattern of chronic sleep deprivation and catch-up suggests that they probably are under-slept overall, which is not good."
He said sleep needed to be treated as seriously as physical activity and nutrition, with the same official national guidelines.
"Currently it's the forgotten eight hours of the day," Prof Olds said.
"But sleep hygiene is really important. Kids need a regular routine and parents should be aware when their kids are not getting enough and put solid habits in place."
The findings also have public policy implications, with experts saying moves to start school earlier would be "disastrous" for already sleep-deprived students.
