Could This Simple Bedtime Habit Hurt You?

A recent study shows that the seemingly harmless habit of using an electronic device, such as an iPad or smartphone, before going to bed can adversely affect your natural circadian sleep rhythm. Your circadium rythm is your natural biological rythm over the course of 24 hours, especially involving sleep which accounts for one-third of your circadium clock (pictured below).

“We found the body’s natural circadian rhythms were interrupted by the short-wavelength enriched light, otherwise known as blue light, from these electronic devices,” said Anne-Marie Chang, PhD, corresponding author, and associate neuroscientist in BWH’s Division of Sleep and Circadian Disorders. “Participants reading an LE-eBook took longer to fall asleep and had reduced evening sleepiness, reduced melatonin secretion, later timing of their circadian clock and reduced next-morning alertness than when reading a printed book.”

Findings, based on a study supported by National Institutes of Health, had twelve participants read e-Books on an iPad for 4 hours before bedtime for five consecutive nights. They then repeated this with printed books instead. Those using the iPad before sleep actually spent less time in deep REM sleep, were less sleepy in the evening and took much longer to fall asleep. The iPad readers also showed reduced levels of melatonin, the hormone which would normally rise in the evening and which plays a role in inducing sleepiness. Their circadian rhythm, as indicated by melatonin secretion levels, showed a significant delay in the circadian rhythm by an hour. Following eight hours of sleep, the iPad users were less alert and were reported to be sleepier.

Although iPads were used in this study, researchers also measured other e-Readers, laptops, cell phones, LED monitors, and other electronic devices, all emitting blue light. “In the past 50 years, there has been a decline in average sleep duration and quality,” stated Charles Czeisler, PhD, MD, FRCP, chief, BWH Division of Sleep and Circadian Disorders. “Since more people are choosing electronic devices for reading, communication and entertainment, particularly children and adolescents who already experience significant sleep loss, epidemiological research evaluating the long-term consequences of these devices on health and safety is urgently needed.”

Emphasis of the importance of these findings, given recent evidence linking chronic suppression of melatonin secretion due to nocturnal light exposure, shows how important it is that we need to change some of our habits. Pickup a printed book next time!

Posted in Life & Health on Sep 05, 2015


Could This Simple Bedtime Habit Hurt You?

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Wow, my circadian rhythm is all types of messed up! I wonder if my use of a PC is adversely affecting me...

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