For years, using a smartphone at bedtime has been akin to the proverbial temptation not to clear customs lines down the local office supply store. New research now suggests that the story is more complex: Adults who go scrolling before lights out aren’t inevitably sleeping worse, and may in some cases sleep as well or even better than those who use screens only on occasion.
What the new study found about adult sleep and screens
For the study, “The Complex Association Between Bedtime Screen Use and Adult Sleep Health,” which was published in the Journal of Sleep Research, researchers from Toronto Metropolitan University and Université Laval surveyed over 1,300 Canadian adults. Accounts among adults, however, did not show a clear association between bedtime screen use and poor sleep after adjusting for age, income and gender.
Those who used screens regularly before bed — five or more nights a week — reported the best sleep timing and daytime alertness. The best satisfied and most consistent sleep was reported by those who used screens rarely. The group caught in the middle of those, which we called “sometimes scrollers,” did worst on multiple measures. That U-shaped trajectory suggests that overall consistency — more so than any draconian no-screens rule — may be the stronger driver of sleep quality.
Why consistency matters for sleep and screen routines
Sleep thrives on routine. Even if a screen is part of that wind-down ritual, the predictable cue sequence helps reinforce regular pre-bed behavior. Irregular habits — sometimes checking email late, sometimes avoiding screens altogether — may introduce variability that delays sleep or otherwise fragments rest.
What content and arousal level has to do with it. While for some, passive and peaceful activities such as a guided meditation or reading saved articles could help relax; doomscrolling, competitive games or work-related messages can spike stress and alertness. The same device can soothe or spark depending on how you use it and when you put it down.
How age and scrolling habits influence sleep outcomes
Age is a game-changer, the group explains. One possibility is that as we age, the eye’s lens naturally yellows and transmits less blue light, so older people may be less sensitive to being exposed to evening light. That may help account for why adults in this study weren’t affected across the board. Adolescents, however, are more sensitive to light at night, and late-night device use was associated with later bedtimes and less sleep in teens in previous research.
And it depends on light intensity and time of day, too. Bright, close-up light late at night can suppress melatonin, as laboratory studies from places like Harvard Medical School have demonstrated. But in reality, behavior isn’t lab behavior: adults frequently reduce the brightness of their screens, shift to a warmer display (more red than blue) and multitask with audio or low-light reading. And then those nuances can diminish the impact of blue light, particularly when embedded within a consistent bedtime.
Practical steps you can try to manage screens before bed
- Run a personal A/B test. Monitor your sleep for a week as you would normally, then do so for a week without screens in the 60 minutes before bedtime. If getting to sleep, staying asleep or waking up doesn’t feel like it’s improving at all, your phone may not be the problem.
- Keep the routine steady. Get up and go to bed at the same time every day, even on weekends. If you do use your phone, set a cutoff — when you get into bed, for instance — and stick to calming content.
- Lower the sensory load. Lower the screen’s brightness, opt for warmer color temperature and use grayscale to minimize visual stimulation. No notifications; no inbox checks late at night.
- Watch for edge cases. If you are struggling with insomnia, shift work or a circadian rhythm disorder, stricter light management might be something to consider. Use bright light in the daytime, and dim light or reduced blue-spectrum lighting should begin a couple of hours before bedtime.
Limitations of the study and what future research may do
This research is based on self-report in everyday life, not laboratory measures like polysomnography, and it didn’t randomize people deliberately into using screens in certain ways.
That means we can’t infer causation. In further work, wearables and light sensors on a trial basis would better define how content, brightness and timing interrelate with individual chronotypes.
Yet the findings are consistent with an emerging body of conflicting evidence: While blue light can alter circadian timing under controlled conditions, real-world sleep is governed by behavior, stress and routine. That kind of practical guidance matters when about 85% of U.S. adults own smartphones, according to Pew Research Center data, and the CDC finds that one in three adults do not get enough sleep. The takeaway: Instead of just blaming your phone, concentrate on consistency, content and cutoff — and then let the data within you tell you what to do.
