Using your phone at night may not be as bad as you think

For many years, the advice of scientists and experts for people of all ages has been pretty universal: Using your phone before bed will ruin your sleep.

But the results reached by A New study Conducted by Université Laval, Toronto Metropolitan University (TMU) paints a more complex picture of modern nighttime habit.

The self-study asked more than 1,000 adults across Canada about their bedtime screen use and sleep health, and found that overall sleep health was similar between those who used screens every night, and those who didn’t use one at all. The worst sleep came from those who used their phones only a few nights a week.

While previous studies have blamed sleep disruption on blue light emitted by phones and other LED screens, which some research says suppresses the body’s production of the sleep hormone melatonin, the TMU researchers said these findings did not take into account age, timing or intensity of exposure.

Read more: 20 things you should not do before bed

TMU Professor Colin Carney, Other studies in this field have used experimental conditions that don’t reflect the average person’s day, and in some cases “stacked the deck” to prove that blue light is the culprit, said one of the study’s authors, who specializes in sleep and mood disorders.

“It’s true that we have those studies, but in order to get these results, these studies usually choose young people who are closer to puberty, which is really important, because that makes you sensitive to light. Then they keep them in the lab all night and all day, and they’re in dim light all day,” Carney told TIME. “I think people have taken the findings in this area and applied them very broadly, and they don’t care about the studies you don’t find.”

Carney says the study found that it’s equally important what people do He does On their phones, especially “if you’re involved in things that make it hard to let go, or if you’re involved in things that are annoying or alarming on your phone.”

the study, Published in magazine Sleep health In October, foMore than 80% of participants reported using screens at bedtime in the past month, and nearly half reported using screens every night.

Carney’s study follows a raft of similar findings in recent years that suggest blue light may have been unfairly distorted.

Research, for years, has pointed in one direction: Blue light can disrupt sleep and potentially delay the release of melatonin, so limiting it is the best way to get a good night’s rest.

Several studies have found that exposure to short-wavelength blue light reduces melatonin levels, thus negatively affecting sleep.

A 2011 study Published in Journal of Applied Physiology Found a link between blue light exposure and melatonin suppression. Another 2023 study published in Brain connections Sleep was measured in adolescent boys and young adults after reading with a physical book or using a blue light-emitting phone. The results supported the idea that melatonin can be inhibited by blue light, but also found that the negative effects could be mitigated if the phone was put away at least one hour before bed. April 2025 study published in the journal life He stressed that blue light disrupts the circadian rhythm, and found that red light was a better alternative.

Other studies have found a strong link between phone use and poor sleep quality, but have been unable to determine causality.

A 2016 study A study published in the journal PLOS ONE and covered by TIME found a strong link between phone use before bed and poor sleep, while no conclusions were made about causality. The 30-day study measured the screen time of 653 adult participants across the United States.

“We cannot rule out the possibility that people who can’t sleep for an unrelated reason are filling that time using their smartphones,” one of the study’s authors, Dr. Gregory Marcus, told TIME in 2016.

In the National Sleep Foundation’s 2024 expert panel of 16 sleep and pediatrics experts, Publish a consensus statement They say screen use in general impairs sleep health in children and teens, but this is primarily due to the content. The committee did not reach a consensus on whether exposure to blue light from screen use before bed could impair sleep in adults.

A March 2025 American Cancer Society study More than 122,000 participants found that daily screen use was associated with later bedtimes and about 50 minutes less sleep each week.

Dr. Alex Demetriou, a psychiatrist and sleep medicine physician in Menlo Park, California, calls the study “astonishing, because it goes against a very large body of research that suggests there is a clear effect on sleep quality from screen use,” citing a 2025 American Cancer Society study as an example.

“The authors acknowledge some interesting findings [including] Causation cannot be clearly determined from this study. It’s possible that people who sleep well either use phones or don’t use them, while people who sleep poorly aren’t sure what to do, Demetriou tells TIME.

In Demetriou’s professional opinion: “Screens are not good for sleep.”

“I can stay awake [for] Hours of scrolling through news articles, blogs, and social media posts. If I try to read a book, I’m out in 10 minutes. “My patients feel the same way,” he says. “The screens, besides being bright, are very interesting.”

The TMU research is not the first of its kind to suggest that blue light may not be the main factor in sleep disruption.

Several other studies also indicate that research on blue light and sleep is mixed. 2022 review in Frontiers in psychology I examined 24 studies to answer this specific question in young people. One in five studies reported decreased sleep quality after blue light exposure, while one in three studies reported decreased sleep duration. Fifty percent of studies showed a reduction in fatigue, consistent with blue light increasing alertness and improving cognitive performance during the day.

“[I]Overall, it appears that the specific effects of blue light exposure remain an ambiguous area and further investigation is needed before definitive, evidence-based conclusions can be drawn, although researchers say blue light “may also have negative effects such as decreased sleep quality and sleep duration, which may worsen an athlete’s physical and cognitive performance and recovery.”

Researchers at TMU note that young people may be more vulnerable to the melatonin-suppressing effects of light, and several studies have found that exposure to light at night can particularly affect children and teens, not the adults on whom the TMU study is focused.

“There may be reason to be cautious about excessive exposure to blue light in the evening for teens, as puberty increases light sensitivity,” Carney said in a statement to the newspaper. “As we age, we become less sensitive to light, and there are age-related effects in the eyes that make light less uncomfortable.”