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.
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| http://www.itats.org/wp-content/uploads/2013/08/ereaders-1.jpg |
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.
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| http://www.howsleepworks.com/images/melatonin.jpg |
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.
Reference:
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).
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?
ReplyDeleteI 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)?
ReplyDeleteI would be interested to know how the various intensities of light affect sleep patterns.
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.
ReplyDeleteAs 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.
ReplyDeleteThis 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.
ReplyDeleteIn 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.
ReplyDeleteUnfortunately, 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.
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.
ReplyDeleteI 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.
ReplyDeleteI 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.
ReplyDelete