Lead author and University of Otago medicine PhD student Chao Gu said her study aimed to answer two key questions - are the recommendations backed up by good evidence, and are the recommendations practical in reality?
"Youth and families are often told not to use screens, not to exercise and not to eat in the hour before bed to ensure a good night’s sleep.
"In reality, we also do not know how many youths are actually following these recommendations."
The study used body cameras and detailed food records to look at what young people did in the hour before bedtime in their typical daily life, and how these "sleep hygiene" behaviours influenced their sleep that night.
She said 99% of participants used screens, 63% ate food and 22% exercised before bed.
"Not many teenagers followed current sleep guidelines, but those who did experienced little difference in their sleep.
"It is very common for youth to use screens, quite common for them to have some food, but less common for them to be very physically active in the hour before bed."
Ms Gu said the results highlighted the need for further research on the topic, and a possible revisit of the present advice.
Researchers were already conducting another study of 10- to 15-year-olds, and hoped it would provide robust and directional evidence for revisions which would help improve bedtime guidance for families.
She said sleep was incredibly important for teenagers to enable them to develop and function at their best.
