(CBS) How much sleep should a child get every night? According to the latest review of a century's worth of sleep recommendations, that answer has changed over the years. But the study found one thing's for sure:
Kids aren't getting as much shut-eye as experts recommend, but neither did their great grandparents.
"We were surprised that over the last century, the actual amount of sleep that children are getting was consistently about 37 minutes less than what was recommended for them," study author Lisa Matricciani, a researcher at the University of South Australia in Adelaide, told MyHealthNewsDaily.
For the study, published online in the Feb. 13 issue of Pediatrics, Australian researchers looked at 32 sets of sleep recommendations that were published between 1897 and 2009, and compared that information to studies and reports on the actual amount of time children slept.
The researchers found that on average, children's sleep recommendations decreased at a rate of 0.71 minutes each year, and that decline was almost identical to the annul decline in the amount children slept (0.73 minutes each year). That means for over a century, children haven't slept as much as expert's recommended, despite the recommendations changing.
In 1897, experts were recommending that children sleep one hour and fifteen minutes more than what's recommended in 2009. The study authors say sleep guidelines are more subjective than scientific.
"Never trust sleep experts," senior study author Dr. Tim Olds, a professor of health sciences at the University of South Australia in Adelaide, told Time Healthland.
Experts' and parents' concerns that kids are too stimulated by their surroundings to get enough sleep is nothing new, the study found, and dates back far to before video games existed. Whether it was books, radio, a new thing called television, or modern day cable, internet, and smart phones, experts blamed these advances for cutting into children's sleep.
What is the optimal amount a child should sleep?
Olds Told HealthDay there probably isn't a sleep standard for kids.
"One child may function best on seven hours, another on 11 hours," he said. Olds said just because a child sleeps late doesn't necessarily mean he's not sleeping enough. He compared sleeping to eating - people might eat when they're not hungry, just as they sleep when they're not tired.
Dr. David Gozal, a childhood sleep expert at the University of Chicago told Reuters, "We need to do due diligence and do the nitty-gritty effort of measuring sleep in a large group of the population to find out what's normal. That has never been done."
Not getting a good night's rest is linked to the development of several chronic diseases, including diabetes, cardiovascular disease, obesity, and depression, according to the CDC. If problems sleeping persist, see a doctor who is familiar with treating sleep disorders.