Wednesday, March 11, 2015

Put Away Electronics for a Better Night's Sleep

We live in a technological era where almost every person in America owns some kind of electronic device. These devices are being used constantly and at all hours of the day and night. A recent study found that 90% of Americans use some type of electronic device a few nights a week in the one hour before they go to bed. How would you feel if you were told that this activity can have negative implications for your sleep, performance, health and safety?

A study conducted by Chang et al. at Brigham and Women’s Hospital in Boston, MA has concluded just that - that using electronics that emit light, specifically an e-Reader, before bed can in fact have adverse effects on various facets of life.

Researchers compared the effects of using an e-Reader with reading a printed book, both for about four hours before bedtime for five consecutive evenings. They found that using a light emitting e-Reader before bed decreases sleepiness, increases the time it takes to fall asleep, and increases sleepiness after awaking the next morning.
The aforementioned conditions can be explained by suppressed melatonin levels induced by using an e-Reader before bed. Melatonin is a sleep-facilitating hormone whose levels rise and fall according to each individual’s circadian clock. The circadian clock is a cycle that is responsible for synchronizing many internal physiological and biological processes. If melatonin levels are altered due to exposure to light emitting devices, the circadian clock shifts and the sleep cycle no longer coincides with the circadian cycle. This also means that in the morning, the circadian cycle is lagging behind which causes melatonin levels to be higher than normal resulting in increased sleepiness. 

Recent evidence has led to the concern that chronic suppression of melatonin levels by nocturnal light exposure can be linked to an increased risk of various diseases such as breast, colorectal, and prostate cancer. It is also conceivable that continuous use of a light emitting electronic device before bed can lead to increased risk of developing a sleep disorder and/or sleep deficiency.

The use of an iPhone, iPad or other e-Reader before bedtime can potentially have devastating effects on health and sleep, yet 90% of Americans are putting themselves at risk. By simply avoiding electronics in the hours before bed, you will likely fall asleep faster and wake up feeling more alert.

1. Chang AM, Aeschbach D, Duffy JF, and Czeisler CA. Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. PNAS, 112:4 1232-1237 (2014). 


  1. I understand that the lights from these devices suppress the production of melatonin, but wouldn't this in some sense suggest that using lights in general before bed suppresses our production of melatonin and therefore we should live in the dark before we go bed?

  2. I like the article, but I agree with Andrew's question. How much light am I allowed to be exposed to before bed? Also, can you force yourself to stay awake by shining bright lights into your eyes or simply surrounding your self with bright lights (caffeine alternative)?

    I would be interested to know how the various intensities of light affect sleep patterns.

  3. I agree with Rehman. They have specific apps for the type of light you are exposed to before bedtime. For example, one application for your computer is called f.lux and it allows you to control the brightness and type of light your computer screen gives off throughout the day, such that at night it dims to a level that supposedly helps to not impair melatonin production. Research into what type of light affects this, and whether apps such as f.lux are actually helpful would be interesting since I do not believe people are willing to sacrifice their technology before bedtime any time soon.

  4. As technological advances continue in the 21st century, it seems that you would be hard-pressed to find an individual without some type of tablet, e-reader, or cell phone that emits light from its screen. Before reading this blog post I had heard general speculation that using electronics of this nature before bed could severely impact the ability to fall asleep, but had not actually seen any concrete proof of this phenomenon. This study gives experimental evidence to back up claims of decreased melatonin production and thus altered sleep cycles. The three other comments all ask a good question: just how much light affects melatonin levels? Is screen brightness really so different from lights around the house before bed? Additionally, the idea that decreased melatonin levels can lead to diseases such as cancer is quite alarming. I would be interested to know how melatonin interacts with cellular signalling and growth to cause cancerous mutations, and how low levels must be to result in these phenotypes.

  5. This is such an interesting article! I have heard that light from electronics causes you to stay awake, but I didn't realize it could have such detrimental effects on health. It's interesting to think about how a hormone (such as melatonin) can have so many different impacts on the body if not properly regulated.

  6. In regards to Drew's question, studies have shown that blue light is able to suppress the production of melatonin and therefore alter the circadian rhythm much better than any other wavelength of visible light. Although all light does contain an element of blue light (like the sun and incandescent light bulbs), the increasingly popular LED and energy-efficient light sources as well as electronic devices emit even more blue light. I don't think people are expected to live in darkness as soon as the sun goes down (although it seems logical to argue that this would lend itself to a great night's sleep), but rather to limit exposure to sources of blue light during the evening.

    Unfortunately, it doesn't seem like anyone has studied the effects of varied amounts of light (or blue light) on melatonin levels or the circadian rhythm, but that is certainly something that can be investigated in the future.

  7. Living in a world where technology is a huge part of people's lives, I find this article to be very interesting. I have always heard to not keep my phone around me when going to sleep, but never for this reason. With college students always being on their phones and computers doing work at all hours of the night, it makes even more sense as to why they would be more tired because of the lagging circadian cycle. Then again, agreeing with the previous comments, how much light is too much light.

  8. I have heard that using electronic devices before bed can disrupt an individual's sleep pattern, but I never knew the scientific background for this information before reading this article. It was really informative, direct, and the studies make sense. I agree with the other commenters in questioning whether how much light is needed to have an impact on the melatonin levels in the body. I also wonder if other aspects of electrical devices have an impact on sleep patterns, such as radio waves or other signals emitted by iPhones, iPods, laptops, etc.

  9. I know that there are some sources which state any light can negatively affect your sleeping patterns. However, I think as Danielle mentioned, and replied in a comment, it has been found that blue light specifically inhibits melatonin production, and since blue light is more associated with LED screens this is what people are exposed to. I have f.lux downloaded on my computer in an attempt to turn down the amount of artificial light I am exposed to, as the program alters the light production based on the time, so that there is more red light at night. So maybe red light stimulates melatonin production? Or at least compared to blue light does not suppress its production.