[WORLD] If better sleep is the goal, it might not be enough to simply switch off the lights—powering down the phone could be just as important.
That’s the conclusion drawn by researchers in Norway, who surveyed over 45,000 university students and found a strong link between bedtime screen use and poor sleep quality. According to the findings, using screens in bed was associated with a 59% higher risk of insomnia and reduced nightly sleep duration by nearly 30 minutes.
The study adds to a growing body of evidence on the disruptive effects of blue light, emitted by smartphones and other digital devices. This light interferes with melatonin production, a hormone essential for regulating the body’s internal clock. Even limited exposure before sleep can push back the time it takes to fall asleep by up to an hour, exacerbating the issue of delayed rest.
While many assume the anxiety of social media engagement is to blame—agonizing over low likes or online spats—the researchers point to screen exposure itself as the primary culprit.
“Screen use itself is the key factor in sleep disruption – likely due to time displacement, where screen use delays sleep by taking up time that would otherwise be spent resting,” said Gunnhild Johnsen Hjetland of the Norwegian Institute of Public Health.
The consequences extend well beyond lost sleep. Research from Harvard Medical School has linked poor sleep, often associated with nighttime screen use, to declines in cognitive performance, emotional regulation, and even cardiovascular health—underscoring the broader implications of digital habits.
The Norwegian team, writing in the journal Frontiers in Psychiatry, found that the type of screen use—whether scrolling through social media or watching videos—made little difference. “Screen use is thought to impact sleep in four ways: notifications disturb sleep, screen time replaces sleeping time, screen activities keep you wakeful so you take longer to fall asleep, or light exposure delays circadian rhythms,” the researchers noted. Their conclusions are based on data from Norway’s 2022 Students’ Health and Well-being survey, which included responses from over 45,000 individuals aged 18 to 28.
Experts increasingly recommend a “digital curfew” of at least one hour before bedtime, replacing screen time with more relaxing activities such as reading or meditation. While smartphone features like "Night Shift" and "Do Not Disturb" aim to reduce disruptions, lasting improvements are more likely to come from behavioral change.
The research also dovetails with a separate study, published April 28 in Frontiers in Communication Science, which found that phone-related distractions may linger even when the devices are set aside. Conducted by Maxi Heitmayer of the London School of Economics, the study observed participants in a controlled environment and found that habitual smartphone users continued to experience lapses in focus and increased procrastination—even without their devices at hand.
“Putting the smartphone away may not be sufficient to reduce disruption and procrastination, or increase focus,” Heitmayer said.
In response, some schools and workplaces are trialing "phone-free zones" to encourage sustained attention. Preliminary results suggest that scheduled breaks from screens, rather than outright bans, may offer a more practical path to improving productivity and well-being.
“Our phones are an endless source of distraction, and we interact with them every four to six minutes,” noted publisher Frontiers.
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