Scientists have found: using your phone before bed doesn't harm adults' sleep

According to a new study by scientists from the University of Toronto Metroplex and Laval University, evening screens do not impair adult sleep. The work is published in the journal Sleep Health.

The study involved more than 1,000 Canadian adults who were asked questions about their screen-use habits before bed and sleep quality. More than 80 per cent of respondents admitted to using smartphones or other devices before bed, and almost half do so daily.

The results were surprising: people who used their phones every night slept just as well as those who didn't use devices at all. Moreover, regular users had better sleep times and higher daytime alertness, while those who used screens infrequently (less than once a week) had better sleep regularity and satisfaction with sleep quality.

The worst sleep performance was found in participants who used their phones several times a week but not every day. According to the researchers, this may indicate that it is not the mere presence of screens before bed that affects sleep, but the instability of routines and habits.

Professor Colleen Carney, a specialist in sleep and mood disorders at Toronto Metropolitan University, explains:

"Previous attention to 'blue light harm' has not taken into account age, duration and intensity of exposure. Adolescents are indeed more sensitive to light as hormonal changes increase susceptibility, but in adults, light has a much smaller impact."

The scientists emphasise: it's not just when you use your phone that matters, but how. Some apps help you relax - such as meditation or music apps - while others, on the contrary, cause stress or excitement, preventing you from falling asleep.

To test the effect of your phone on your own sleep, Prof Carney suggests a simple experiment:

• one week, use the device as normal;

• the second week - completely avoid screens for at least an hour before bedtime.
  If the quality of sleep improves, you can fix the new habit. If there is no change - then the phone is not the problem.

"If you use your smartphone before bed and feel rested - it's likely that it's not bothering you," notes Carney. - "Our results suggest that for adults, screen time before bed is not as dangerous as we have been led to believe."

The researchers emphasise that the findings do not apply to children and adolescents, for whom light from screens may actually disrupt melatonin production and the sleep cycle.

Nevertheless, for adult users, the new work shatters the myth that any evening contact with gadgets is bad for health. It all depends on content, regime and personal habits.