Sleep and screens are not good bedfellows, and young people who use their smartphones at bedtime are getting significantly worse and less sleep, according to new research by scientists in the US.
In the study, people aged between 15 and 18 had their sleep monitored using fitness trackers. Participants also recorded their screen time, the number of notifications they received and when they looked at their mobile phones.
One key finding was that if the teens had more screen time at night compared to their average, they fell asleep later and had poorer sleep.
The same applied to frequently unlocking their mobile phones at night. According to the team of researchers in the US state of North Carolina, smartphone use during the day had no influence on sleep outcomes.
For Frank Erbguth from the German Brain Foundation, the results of the study are worrying.
"We know how important sleep is for the recovery of the body and mind, especially the nerves and brain. Disturbed sleep reduces quality of life and can make you ill."
It is therefore all the more worrying when young people set a course for lifelong sleep disorders through their media consumption.
Erbguth advises parents not to tackle the problem with bans. The study also showed that the young people themselves had noticed the connection between mobile phone use and their sleep problems.
For him, this is a good starting point for raising awareness - the keyword being media literacy. "Because knowledge is always the basis for sensible decisions."
Ultimately, targeted campaigns have also led to a continuous decline in the smoking rate among young people, he says, citing an example from another area.
But why does looking at a mobile phone at night actually lead to poor sleep? For one thing, young people tend to fall asleep much later once they get hooked on the likes of their TikTok and Instagram feeds.
Another reason for sleep problems is the screen light of smartphones. This is because, like televisions, they produce a blue light that impairs the release of melatonin, the hormone that helps our bodies to shut down for the night.