How Blue Light Can Increase Sleep Problems

Before the invention of artificial light; the sun, candles and lanterns, were the only way to illuminate the world around you after sunset. It was often said, that a few hours in the sunlight makes for a good nights sleep!

Light researcher Mariana Figueroa of the Rensselaer Polytechnic Institute, investigated how light affects human health, and her recent research focused on finding out which electronics emit blue light intense enough to affect sleep. When comparing melatonin levels of adults and teenagers looking at computer screens, she was astonished by the younger group’s light sensitivity. Even when exposed to just one-tenth as much light as adults were, the teens actually suppressed more melatonin than the older people.

In another experiment, she had adults use iPads at full brightness for two hours and measured their melatonin levels with saliva samples. One hour of use didn’t significantly curtail melatonin release, but two hours’ did.

Ordinarily, the pineal gland, a tiny (pea sized) organ in the brain, begins to release melatonin a couple of hours before your regular bedtime. The hormone is not capable of making you go to sleep immediately, but it does reduce alertness and make going to sleep more inviting.

Light, especially blue light — can keep the pineal gland from releasing melatonin and preventing you from becoming drowsy. You don’t have to be staring directly at a television or computer screen: If enough blue light hits the eye, the gland can stop releasing melatonin. So easing into bed with a tablet or a laptop makes it harder to take a long snooze, especially for sleep-deprived teenagers who are more vulnerable to the effects of light than adults.

During adolescence, the circadian rhythm shifts, and teens feel more awake later at night. Switching on a TV show or video game just before bedtime will push off sleepiness even later even if they have to be up by 6 a.m. to get to school on time.

What to do?

  • Use dim red lights for night lights. Red light has the least power to disrupt circadian rhythm and suppress melatonin.
  • Spending a lot of time in the bright light during the day will help you sleep great at night.
  • If you must use your computer in the evening, download the free program f.lux. It adjusts the brightness and color temperature of your computer’s display according to the time of day.
  • Do not look at bright screens two to three hours before bed.


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