Quality sleep – and getting enough of it – is strongly linked to our mental and physical health.

For kids, getting the right amount of sleep is also essential for things like healthy growth, regulating emotions and their ability to function well at school.

But new data released this week reveals that half of 16-17 year old Australian kids – and around a quarter of 12-15 year olds – aren’t getting enough of it on school nights.

The Growing Up in Australia Longitudinal Study of Australian Children (LSAC), which studied the sleep patters of Australian kids –  has also found links between a shorter sleep time and higher rates of anxiety and depression.

Catch-up sleep on the weekends is common for those kids not getting enough shut-eye on school nights, but is not necessarily the answer, says Australian Institute of Family Studies Research fellow Dr Tracy Evans-Whipp.

“This ‘yoyo’ pattern across the week increases with age,” Dr Evans-Whipp says.

“It also leads to disrupted sleep wake cycles and goes against the sleep guidelines which advise regular sleep and wake times.”

The take-home message: it’s important for parents to set regular bedtimes – even on weekends and holidays – from the time their children are young.

Some background on sleep

National guidelines recommend that children aged five-13 years have between nine and 11 hours sleep and adolescents aged 14-17 get between eight and 10 hours.

A pattern of regular sleep and wake times is another essential ingredient for healthy sleeping.

“The exact amount of sleep needed varies from person to person and also within individuals according to age and daily variations in physical activity, illness and recent sleep patterns,” the report says.

“Guidelines therefore provide maximum and minimum ranges for the number of hours of uninterrupted sleep in each 24-hour period.”

The good news from the data is that most kids aged six-11 are getting enough sleep on school nights.

The influence of physical activity, caffeine and screen time

It’s hardly rocket science that our activity levels and caffeine consumption affect our ability to sleep well, and the study has confirmed those links.

“The study found that obese 12-13 year-olds were more likely than those in the normal weight range to not meet minimum sleep guidelines,” Dr Evans Whipp said. [This difference was not found in the older age groups.]

“Children aged between 12-13 years and 14-15 years, who participated in sport, were more likely to be getting enough sleep, suggesting that physical activity is associated with longer sleep times.”

Older teens are the age group that may need to be monitored the most, says Australian Institute of Families Studies director Anne Hollands.

“The group most at risk of not getting enough sleep on school nights is older adolescents who may need to be taught how to improve their sleep by reducing caffeine intake, limiting internet use before bedtime, keeping a consistent sleep routine and getting plenty of physical activity.”

So what time are other parents putting their kids to bed?

The LSAC data also gives an insight into what time Australians are putting their children to bed.

The average bedtime on school nights for six to seven year olds was around 8pm. On non-school nights, it moved back to 8.40pm.

The average 16-17 year old went to bed at around 10.15pm on school nights and between 11pm-11.30pm on non-school nights.

The other common trends identified were that bedtimes on both school and non-school nights get later as children get older – and are about an hour later on non-school nights across all ages.

[The report notes that “during adolescence biological rhythms change in response to puberty causing sleep patterns to shift towards later times”.]

On average, children of all ages woke up at around 7am on school mornings.

Want to know more?

Read the report in full and a summary of the data in the Australian Institute of Family Studies media release.

Find the latest National Sleep Guidelines here.

Listen to an ABC radio report on the study here.