The Sun, Your Sleep and the Solar Eclipse
You've probably heard that the United States will experience a unique event on August 21, 2017. Those of us in the contiguous United States have not seen a total solar eclipse since 1979, and incredibly, Monday's eclipse will be seen from coast-to-coast.
But, there's a lucky area who will truly have an experience of a lifetime. There is a 70-mile wide path that spans the US in which the sun will be completely covered by the moon (known as totality) where the stars will shine, the air will cool and the sun's atmosphere will become visible for a matter of minutes. Since this moment puts our sun -- and moon -- at the center of our attention, this is a good opportunity to highlight just how important our closest star is to our well-being.
Humans and the Solar Connection
Our bodies are more connected to the sun than you may realize. All living things on Earth are intimately linked to the sun. Millions of years of evolution on a planet with a 24-hour day and night cycle allowed the living world to develop an internal body clock, known as the circadian rhythm. Not only does our circadian rhythm guide us on the best times to sleep, eat and interact with others, but it also keeps our organs and cells working in a proper rhythm.
Our circadian rhythm follows the same 24-hour cycle as Earth and the timing of sunlight is the main force behind setting our internal clocks. When our eyes see bright lights, particularly sunlight, our brains are signaled to be awake, while the darkness triggers secretion of the sleep hormone known as melatonin.
The Wrong Timing
So, what happens when your body clock does not align with the timing of the sun?
Perhaps the best example of this is when you travel across time zones. Your body will try to remain on its home timing, while the place you are visiting will be set to a different time. Due to this misalignment, you may have to sleep and wake at times you are not accustomed. This leads to fatigue, poor sleep and irritability, commonly known as jet lag. Over time, your body will readjust to the clock at your new location thanks to help from the sun, but depending on how far you've traveled, this can take days.
The Eclipse and the Circadian Rhythm
If sunlight is the main factor in our body clocks, you may be wondering just how your body will react if you are in the path of the total eclipse. Will you suddenly feel sleepy when it gets dark? Will it be easier to sleep at the end of the day? Will your body clock be thrown out of sync?
In actuality, the eclipse will have almost no impact on your circadian rhythm and this is all due to timing. We are most sensitive to light exposure, and the lack thereof, in the early morning and late evening. The longer the light and dark exposure lasts, the more it impacts our body clocks. Since the total eclipse will last less than three minutes and is occurring in the middle of the day, it will not impact the timing of your circadian rhythm at all. Rest assured that the spectacle will come at no cost to your body's well-being.
Hopefully, the weather will allow everyone in the path of totality to see the eclipse in its full glory on Monday. And while you marvel at how amazing the solar system can be, take a minute to remember just how closely you and your body are connected to the sun.