Reading From a Tablet at Bedtime affects Sleep quality – Study

A new study has found that people who read for 30 minutes from an iPad instead of a physical book before bedtime are likely to feel less sleepy. This is due to the differential electrical activity in the brain during sleep.

Researchers at the University of Bergen in Norway conducted the study on 16 non-smokers age 22-33 who had no sleep, medical or other psychiatric disorders. They were asked to keep a normal sleep-wake schedule for one week before the study began.

The study lasted for 3 days – one night to observe the normal sleep schedule of each person, the second night to observe the effect of reading from an iPad for 30 minutes before turning off the light and the last to observe the reading from a physical book for the same amount of time.

Polysomnographic recording including electroencephalograms (EEG) was used by the researcher’s to monitor the participants’ brain activity and it collected data on total sleep time, sleep efficiency, a percentage of time spent in each sleep stage, and other aspects of sleep quality.

The light meter used to measure illumination at eye level revealed that reading from an iPad resulted in 50 percent higher illumination levels than reading from a physical book. But the time took to fall asleep and the length of the sleep remained the same in both cases.

However, on examining the EEG readings the lead study author Janne Gronli.said, "We found a delay of 30 minutes in the generation of the restorative slow waves during sleep in the iPad condition. " And hence, the quality of sleep is affected much.

The researchers cannot compare the iPad light and bedroom light since they measured only the illumination. Moreover, some bedroom lights may emit a higher amount of blue light than the iPad.

The team also accepted a limit of their study since only one night of reading from an iPad was considered and also, only a limited sample was tested. The researchers are speculated to find the effect of daily usage of all blue light emitting device before bedtime.

Though researchers couldn’t find the cause-and-effect relationship, they still recommend people to use the bedroom for sleep and not for work or social media.

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They also recommend using night mode which is the latest update in both Apple and Android devices since they filter the amount of blue light emitted at night time.