Sleeping in the Shade

Everyone runs on a clock. Whether we run on the time from our watches, on a sundial, or from the clocks on the screens of our phones, we are primed to live our lives alongside the ticking of these clocks. We seem to be under the control of the time we are given throughout the day. However, we fail to recognize that in a small part of our brain, there are tiny clocks that control us in more ways than we understand. While we do wake up and sleep along with the rising and setting of the sun, our internal clock, or circadian rhythm, has a much greater control in this cycle than is seen.

Normal Circadian and Homeostatic Sleep Drive
(howsleepworks.com)

Our circadian rhythm runs on external cues, such as light, to entrain us to the 24-hour cycle that is our normal day. Circadian drive also works along with homeostatic drive to regulate our sleep-wake cycles. Homeostasis is our bodies' ability to maintain its stability. Our homeostatic drive to sleep is an indicator that our bodies are feeling the pressure to sleep in order to maintain its stability. This usually occurs during the evening, which explains why we want to sleep at night. But what makes us want to sleep at night instead of during the day?

In "The Drosophila Circadian Clock Gates Sleep through Time-of-Day Dependent Modulation of Sleep-Promoting Neurons," Dr. Cavanaugh concluded that our circadian clock, also known as the suprachaismatic nucleus (SCN), has a direct role in the regulation of sleep, and actively inhibits sleep at specific times throughout the day. Our internal clock designates the time when melatonin is secreted. The SCN inhibits melatonin release in the presence of light, which is why we stay active during the day. Melatonin is secreted, by order of our internal clock, in the evening, which causes us to feel sleepy. When our circadian drive fluctuates to a higher level, combined with the higher homeostatic drive to sleep, we begin to feel tired and fall asleep easier. 

This seems to work well until we begin to watch TV, use our computers, or check our phones. Because our eyes use light to entrain to the light and dark cycles of our day, light has an important role on SCN stimulation. The blue light from our technology stimulates the SCN to delay the release of melatonin, preventing us from falling asleep when we should. We would never think that these would be the culprits to many sleeping disorders or health problems, but the artificial blue light that is emitted from these screens inhibits circadian control of melatonin, preventing us from falling asleep, even when our homeostatic drive to sleep is high. Because we live in anticipation of food intake and threats while awake, as opposed to when we are asleep, our metabolism and cortisol levels are higher in the day. When we throw our cycles out of whack, our bodies fail to power off, and our metabolism and stress response systems become active when they shouldn't be.  

This artificial blue light does a lot more damage than we would like to believe. The longer we stay awake, the more cortisol, our bodies' stress hormone, is released. When cortisol is released over a long period of time, it has negative effects on our bodies' immune systems. The inability to sleep well most clearly causes insomnia and other sleep disorders, but it is less prominently known to cause a weakened immune system, higher incidence to obesity and diabetes, higher risk of cardiovascular diseases, and increased risk of mood disorders and depression. Rather than treating the many negative and dangerous effects of the artificial light, we need a way to prevent them from happening.

The unsurmountable issue is that these forms of technology are so integrated in our daily life, that it seems nearly impossible to remove them and live in a life without this blue light. And we shouldn't have to.

Amber Lens Reduces Blue Light from Entering the Eye
(psychologytoday.com)

Recent studies at Harvard University have supported that the removal of blue light, especially later in the evening when the sun would set, allows our internal clocks to release melatonin and help us fall asleep better and stay asleep longer. Scientists have looked into amber-tinted sunglasses that block the blue light from entering our eyes. But is wearing a pair of shades really the scientific shield to all of the negative effects of the menacing blue light? Of course it is! By reducing the strain that blue light has on the SCN, melatonin release can be better stimulated at the right times, reducing the increase of cortisol release in the body, and finally improving our immune systems. 

And the best part about this solution: no side effects! (Unless looking super cool indoors is considered a side effect.)

Amber-tinted Sunglasses (psychologytoday.com)

Further research is necessary to test the true effectiveness of these amber-tinted shades, but it is clear to see that reducing this blue light in our lives tremendously improves our sleep schedules, and, in turn, reduces the risks for all of negative side effects that melatonin delay brings. We need to think twice about our use of technology, and take precautionary measures to prevent these negative effects. Whether it's limiting the amount of TV time before bed or using the ambient mode on our iPhones, it is important that we take the initiative to take control back of our internal clocks. Nonetheless, putting on a pair of sunglasses seems to be the easiest (and coolest) way to prevent this blue light without sacrificing our technology-driven lifestyles. 

References:


Cavanaugh, Daniel J., Abigail S. Vigderman, Terry Dean, David S. Garbe, and Amita Sehgal. "The Drosophila Circadian Clock Gates Sleep through Time-of Day Dependent Modulation of Sleep-Promoting Neurons." Sleep 39.2 (2016): 345-56. Web. 24 Feb. 2017. 

Haseltine, Eric, Ph.D. "A Cheap New Wonder Drug?" PsychologyToday.com. N.p., 13 Jan. 2017. Web. 24 Feb. 2017. 

"Sleep - How Sleep Works - The Two-Process Model of Sleep Regulation." Sleep - How Sleep Works - The Two-Process Model of Sleep Regulation. N.p., n.d. Web. 28 Feb. 2017.