A new study has found that adults who use their cell phones before bed lose about an hour of sleep per week.
While it is widely accepted that screen time before bed affects sleep quality, a new analysis of more than 122 people has clarified the exact impact of these behaviors, according to the journal The Telegraph.
People who used their phone, tablet or laptop daily before bed slept an average of 48 minutes less per week.
The study also found that regular users of these devices were more likely to fall asleep later.
The researchers, led by experts from theAmerican Cancer Society, collected data on adults in the United States and Puerto Rico, including their sleep habits and screen use – excluding television – during the hour before bedtime.
About 41% of participants reported using a screen before bed every day, while 17% said they never do so.
People who used their phones before bed daily were 33% more likely to complain of poor sleep compared to those who did not use any screens in the hour before bed.
The research team divided the participants into two groups: up early and night owl, depending on whether they preferred to be active early in the morning or late at night. The first category represented 58% of the sample.
The results showed that the up early Using a screen before sleeping fell asleep about 9,33 minutes later on workdays than those who did not. night owl, meanwhile, delayed their sleep time by 15,62 minutes on weekdays, and the results were similar on rest days.
The researchers pointed out that light emitted by screens could play a role in these effects.
They wrote: "Light exposure at night can disrupt sleep by altering this natural cycle by delaying melatonin secretion, which can reduce feelings of sleepiness and increase wakefulness."
However, they clarified that sleep disturbances related to screen use "may not be limited to the effects of screen light," adding that "it is not only the light emitted by these devices that needs to be considered, but also the content displayed."
They also noted that social media is a major source of content consumed on mobile devices, but that "very few studies have examined social media use before bedtime."
The link between screen time and reduced sleep was more pronounced among night owl, that is, those with an evening chronotype, who are more active later in the day.
The researchers explained that these individuals are already at risk of sleep deprivation due to "body clock disruption" or the "mismatch between natural rhythms and social obligations." In other words, they prefer to go to bed late, but due to work or school, they are unable to do so.
The researchers concluded: "Our findings strengthen the evidence that screen use and sleep duration and quality disorders are not just a concern for children and adolescents, but also for all adults."
