In an attempt to gain alertness, 85% of Americans consume at least one caffeinated beverage per day. What if there was a proven, drug-free behavior that could boost alertness as effective, or possibly even more effectively than caffeine? A recent study had twenty four subjects perform a series of psychomotor reaction-based tasks after ingesting either 240 mg of caffeine or a placebo (a sugar pill) and exposure to blue light or a placebo (white light). In the early stages, the caffeine group kept up with the blue light group, as they both exhibited excellent reaction times compared to the placebo groups. On the executive function tests, however, where subjects were instructed to tap the correct answer as quickly as possible, not only did the blue light group click their answers faster, but the caffeine group also chose far more incorrect answers. On top of this, when a distraction was introduced, the blue light group scored even better. The organizers noted that “the blue light treatment consistently showed beneficial performance effects when compared to the CAF [caffeine] condition.” For a non-drug, non-addictive, side effect free behavior, these results deserve more attention.
The boost in alertness, however, is perhaps one of the least noteworthy benefits that blue light has on the body. The digestive system, muscular system, behavioral patterns, and individual organs like the pancreas and spleen, all work differently during the night than during the day. This phenomenon is known as circadian rhythm, the daily internal cadence through which the entire body functions. A healthy circadian rhythm can positively influence mood, sleep, alertness, hormone production, and much more. A distorted circadian rhythm, on the other hand, can have serious disruptive effects on the body’s functions. Natural blue light is visible around the time of sunrise (plus about two hours), and viewing it will correctly set one’s circadian rhythm.
Human eyes are a fascinating, unique part of our bodies. The neural retinas, in particular, which line the back of the eyeballs, are the only component of the central nervous system outside of the skull and spinal cord. They were deliberately placed there to sense light in the environment and relay that information to every other cell in the body. Therefore, to properly set the circadian rhythm, one must feed the retina light information. In short, one must see light.
The common ‘blue light is bad for sleep’ trope must be taken into context. As mentioned, early morning blue light sends a signal to the suprachiasmatic nucleus–the internal clock which sits right above one’s mouth. Ironically, it allows one to fall asleep about sixteen hours later. A systematic review of a number of studies, however, proved that “[l]ight exposure in the evening and at night can suppress and delay (phase-shift) the normal melatonin secretion.” Blue light can be bad for sleep. It can also be beneficial for sleep by facilitating a healthy circadian rhythm. It just depends on when one views it.
Lastly, the assurance that ‘sleep is only tangentially related to mental health’ is a heinous understatement. A comprehensive study published last year claimed that “[a]altered circadian rhythms are commonly reported among individuals with several psychiatric disorders, including major depressive disorder, bipolar disorder, anxiety, and schizophrenia.” The findings prove that circadian rhythm disruption “may elicit or exacerbate symptoms in individuals with a predisposition for mental health disorders[,]” and in rodent models, “resynchronization of circadian rhythms improve[d] symptoms of mood disorders.” Blue light is a double edged sword. But the greatest takeaway is that, when viewed in the morning in the form of sunlight, it will bolster one’s internal clock and can boost productivity, which in turn prevents mental health disorders.
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