If you use smartphones and tablets in bed at late nights, you already know how they have been spoiling your sleep. Studies have shown that the use of blue light emitting devices such as smartphones, tablets or computers during evening hours prevents our brain from producing melatonin – a hormone that lets our bodies know it’s time to sleep, making us longer to fall sleep. Now, researchers from Uppsala University have found a possible way to combat sleep disturbances associated with use of electronic devices, and that is – by increasing exposure to daytime light.
For the study, 14 participants were volunteered to investigate the effects of evening reading on a tablet computer on sleep after having exposed to daytime bright light (approximately 569 lux) over a period of 6.5 hours. While some participants were asked to read a novel (for 2 hours) on a tablet before sleep, the others were given physical book. About a week later, experiments were repeated. The volunteers kept on reading, but switched over from tablet to physical book, and vice versa. Every time the experiments were performed, concentrations of saliva melatonin, sleepiness and quality of sleep were repeatedly measured.
The team found no difference in sleep parameters and pre-sleep saliva melatonin levels (in both – tablet and physical book reading conditions) following exposure to daytime bright light.
“Our main finding was that following daytime bright light exposure, evening use of a self-luminous tablet for two hours did not affect sleep in young healthy students”, says Frida Rångtell, lead author of the study, in a press release.
“Our results could suggest that light exposure during the day, e.g. by means of outdoor activities or light interventions in offices, may help combat sleep disturbances associated with evening blue light stimulation. Even if not examined in our study, it must however be kept in mind that utilizing electronic devices for the sake of checking your work e-mails or social network accounts before snoozing may lead to sleep disturbances as a result of emotional arousal”, says Christian Benedict, associate professor at the Department of Neuroscience.
- Source: Uppsala University
- Reference: Two hours of evening reading on a self-luminous tablet vs. reading a physical book does not alter sleep after daytime bright light exposure – Sleep Medicine