A small study from Norway suggests that people who use a tablet just before bedtime have trouble falling asleep, and their brain activity is different than people who used a print book.
Researchers also found that only 30 minutes of reading from an iPad under the covers has a negative impact on sleep. A study detailing the findings was published Tuesday in the journal Sleep Medicine.
The study’s initial goal was to see whether the background light emitted by iPads had any meaningful impact on sleep quality. To achieve the goal, researchers compared results with data from people who read traditional books.
The research involved 16 students with the median age of 25.1. Participants were allowed to sleep in their own homes so that study results won’t be compromised. Researchers used a tool called polysomnography to detect any sleep disorders. No participant had troubles with sleep before the study.
Polysomnography is a test that monitors brain’s electrical activity, heart rate, eye and leg movement while the subject is asleep. Researchers also measured the amount of light the participants’ eyes received before bedtime. Volunteers were also asked to keep “sleep diaries” for subjective assessments of sleep quality.
Each volunteer was asked to read from an iPad and a book respectively and underwent polysomnography for each separate scenario. Scientists found that the level of illumination was a lot greater when a tablet was involved.
Sleep diaries also showed that reading from an iPad made volunteers feel less sleepy. Brain scans also showed that slow wave activity was severely reduced in participants reading from an electronic device.
Nevertheless, there was no visible impact of reading from a tablet in sleep state timing. Researchers noted that although participants did not report a difficulty in falling asleep in their diaries, tablet use before bedtime “acutely” impacted sleep quality and parameters measuring it such as sleepiness and the slow wave activity.
Scientists believe most commercially available tablets impact sleep because of the blue-enriched light they emit. The findings are consistent with past research that had unveiled a link between blue light emitted by electronic devices and a poor sleep quality during the nighttime and alertness during the daytime.
The research team, however, noted that their research has some limitations due to the small number of participants and the way the study was conducted. Plus, only one e-reader was tested, an iPad, so drawing any final conclusions may be premature.
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