Biggest-ever Canadian research study of its kind shows bedtime screen use isn’t a clear-cut sleep health concern

Worried that staring at a screen in the hours before bedtime could be bad for the quality of your sleep? 

Toronto Metropolitan University (TMU) psychology professor Colleen Carney has some reassuring news: for most adults, bedtime screen use may not be that big a deal.

“I think we've gone a little too far with this obsession about no devices (at bedtime),” professor Carney said. “A device is not going to inhibit sleep forever. It's just not. It's not that powerful.”

The director of TMU’s Sleep and Depression (SAD) Laboratory, and a member of a national sleep research consortium funded by the Canadian Institutes of Health Research, professor Carney specializes in the study of sleep and mood disorders, including insomnia and depression. 

Working with colleagues from multiple Canadian universities, professor Carney recently co-authored a paper, “The complex association between bedtime screen use and adult sleep health.” The goal was to determine whether bedtime screen use is associated with sleep health, and whether any association varies by biological sex, age and income.

Screens at bedtime get a bad rap

The authors believe their research, based on telephone interviews and sleep-health questionnaires with more than 1300 people, represents Canada’s biggest-ever examination of the association between bedtime screen use and adult sleep health. 

Screen use at bedtime is seen as a potential sleep inhibitor because of the blue light emitted by phones, tablets, TVs and computer screens. It’s the same spectrum of light we naturally get from the sun.

What the research found, however, suggests that regular screen use before bed isn’t necessarily the sleep impediment it’s often made out to be.

“This study is correlational, so it's limited, but even with a correlational study, we found that people who use devices at bedtime actually did pretty well,” professor Carney said. “I thought that was really interesting. ”

Measuring different dimensions of sleep health

Participants rated different aspects of their sleep health using the RU-SATED questionnaire, which measures sleep regularity, satisfaction, alertness, timing, efficiency, and duration. 

The study found that less frequent bedtime screen use is generally associated with sleep regularity and higher sleep satisfaction. Overall, however, bedtime screen use frequency “was not significantly associated” with sleep duration or efficiency. 

Nearly 83 per cent of those surveyed reported at least one instance of bedtime screen use in the previous month, with 45 per cent saying it was a daily habit. Male and female subjects reported similar amounts of bedtime screen use.

According to the research, however, the association between bedtime screen use frequency and total sleep health scores was “not significantly moderated” by either biological sex, age, or income level. 

Both occasional (less than once per week) and regular bedtime screen users (at least five times per week) reported the best overall sleep health. Occasional bedtime screen users had the highest levels of sleep regularity and satisfaction, while regular users had the best sleep timing and daytime alertness.

The outcomes align with a 2024 statement from the U.S. National Sleep Foundation, which found enough scientific evidence to say bedtime screen use can impair sleep health for children and adolescents but acknowledged "conflicting data” regarding the impact on adults.

As professor Carney points out, how people interact with screens at bedtime tends to have a greater impact on sleep health than the screen itself. For instance, reading distressing news or playing a first-person video game might delay sleep more than watching a relaxing show or movie. Some people use screens for apps and games that are specially designed to induce drowsiness.

“It's a much more complicated story,” professor Carney said. “What I love about this study is that it reflects that.”

Even for those who struggle to sleep, professor Carney doesn’t believe in blaming screens.

“Look at your relationship with screens and devices. Are you using them because you're having trouble sleeping and it's passing the time? If that's the case, make sure you do it outside the bedroom so you don’t pair your bed with wakeful activities."

Read The complex association between bedtime screen use and adult sleep health (external link, opens in new window)  in Sleep Health.

The research described in this article was supported by the Canadian Institutes of Health Research.