Studies have shown that bright light, such as sunlight, can reset your internal sleep clock, making your body think that it is daylight and time to be awake. It's not just sunlight that's an issue, however. New research shows that using electronic devices such as laptops or iPads right before bed will shine bright lights into your eyes, giving you the same reset result. Your body can be fooled into thinking it's time to be awake, which can interfere with getting a good night's sleep.

iPads Or Laptops Can Disrupt Your Sleep Patterns

Sleep expert Phyllis Zee, a professor of neuroscience at Northwestern University, said that using a laptop or iPad shortly before bedtime can create enough light that it stimulates your brain to be more awake. This can make it harder to get to sleep, and exacerbate any tendencies towards insomnia.

She also stated that this bright light could be enough that it affects your body's circadian rhythms. This is the natural body clock that controls when you feel tired, go to sleep, and wake up again. 

Why Some Devices Pose A Greater Problem

Another sleep researcher said that these problems are not new, and that they have been a concern ever since the invention of electric lights. However, some people feel that the popularity of the iPad for reading in bed at night poses a particular problem. 

If you read a book in bed, you see only a relatively dim light reflected off the page in front of you. If you read on one of the monochrome Amazon Kindle devices, the effect is similar, since it does not emit its own light. An iPad; however, shines light from its screen straight into your eyes, and it does so from a very short distance.

Alon Avidan, an Associate Director at the Sleep Disorders Center at UCLA suggests that people should go back to reading old-fashioned paper books before bed, by the light of a bedside lamp that is not too bright. He said that people who do this would probably be able to relax and sleep better.

Your Biological Clock And Melatonin

Humans are naturally adapted to be awake when the sun is up, and asleep when it is dark outside. When bright lights hit your eyes, it sends the message to your brain telling you that it is time to wake up. Your brain then stops secreting melatonin, an important hormone that is only produced in your body at nighttime. Melatonin helps you become drowsy, and it helps to regulate your internal body clock.

In a natural setting, your brain starts generating melatonin around 9:00 or 10:00 PM, and that helps you get a good night's sleep. However, if you have the lights of a laptop or tablet shining in your eyes, this melatonin generation may not happen when it should.

An additional concern is that our eyes sense blue light in particular, which is common during daylight. Computer screens, tablets, and smart phones all generate a significant amount of blue light, which might intensify the body's tendency to interpret this as daylight. If you've had trouble sleeping, skipping the iPad or iPhone before bedtime could be a good first step to take.