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Avoid artificial light from digital devices at bedtime for better sleep


The artificial light from digital devices could undermine your quality of sleep.

It has been reported by the University of Houston that quality of sleep may be lowered by artificial light from digital devices. Researchers have found that blue light which is emitted from digital devices may be contributing to a great deal of dysfunctional sleep.

In this study when participants wore short wavelength blocking glasses three hours prior to going to sleep for two weeks while they were still taking part in their evening digital routine there was a 58 percent increase in their evening melatonin levels. Melatonin is the chemical which signals to our body that it is time to go to sleep.


Dr. Lisa Ostrin, who lead the study, said the melatonin levels in these people were even higher than increases seen when over-the-counter melatonin supplements are taken. It is highlighted by Dr. Ostrin that

blue light in the evening really does lower the quality of your sleep. Sleep is essential for the regeneration of many vital functions in our body.

The participants in the study who wore short wavelength blocking glasses reported that overall they slept better, fell asleep faster, and slept longer by about 24 minutes a night. Sunlight is the largest source of blue light. Blue light is also found in most LED-based devices.

Alertness is boosted by blue light which also regulates our internal clock or circadian rhythm, which tells our bodies when it is time to sleep. Photoreceptors which are called intrinsically photosensitive retinal ganglion cells (ipRGCs) are activated by this artificial light and this suppresses melatonin.

Dr. Ostrin has suggested limiting screen time on digital devices in the evening. She also suggests using screen filters, wearing computer glasses which block blue light, or using anti-reflective lenses which offset the effects which artificial light have at nighttime. There are night mode settings which limit blue light exposure on some digital devices.

This study has been published in the journal Ophthalmic and Physiological Optics. There seems to be an association between exposure to increasing amounts of artificial light during the night and the high prevalence of reported dysfunctional sleep.

In this study subjectively measured sleep quality along with objectively measured melatonin levels and duration of sleep were increased with the use of short wavelength blocking glasses. It appears that decreasing exposure to short wavelength light after sunset may help to regulate sleep patterns.


Dr Harold Mandel