Blue Light VS Melatonin
Definition: Blue light is a visible energy wave that emits short and high energy ( 450 - 495 nm ) on the electromagnetic spectrum. The electromagnetic spectrum contains visible colors, red through violet, that humans can perceive because of photoreceptors and light reflection onto the retina, to then turn the perceived light into electric signals traveling via the optic nerve.
Definition: The optic nerve, also known as cranial nerve two, is a critical nerve serving as the transmitter for electrical signals to the occipital lobe. Located in the back of the eye. This nerve's transmitted information enables the interpretation of information, thereby allowing for the perception of images.
Blue Light vs. the Others
As stated previously, not only does blue light impair the production of melatonin, but all forms of light can affect it as well. So does blue light have more of an impact? Yes, yes it does. As noted by the CDC, “Blue light has the strongest impact on the circadian rhythm”. Exposure to blue light’s short wavelengths and high energy during critical times before bed sends a stronger signal from the retina, causing the suppression of melatonin production, ultimately shifting the circadian rhythm.
Choose a healthier Lifestyle.
Interruptions to an adolescent's circadian rhythm can be extremely harmful to the growth of the child. Causing issues in mental health, like behavior problems, cognitive function, such as memory retention, and even physical health, causing a suppression of growth hormone.
You can choose a healthier life by balancing blue light technology. To do this, avoid using devices with the lights off, one to two hours before bed, and consider activating a “night mode” on applicable devices. Additionally, adjust the lighting on your phone before bed.
No Phones Before Bedtime
Blue light has been present since the dawn of time, as the sun emits natural blue light waves. However, recent research suggests that blue light emitted from devices like smartphones, TVs, computers, and tablets can disrupt sleep patterns by impairing melatonin production. Melatonin is the key factor in the human body's circadian rhythm. The body emits melatonin roughly two to three hours before a person goes to bed. However, this process is impaired when blue light energy waves come into contact with the retina.
Specifically, when an individual uses a device emitting blue light in a dark area, such as using a phone close to bedtime with the lights off, since melatonin is only stimulated in the dark, any form of light, especially blue light, can interrupt this process, causing a lack of sleep and disparities in one's circadian rhythm.
Did you know?
Blue light energy waves are responsible for the sky appearing to be blue.
Work Cited
CDC. “Module 2. The Color of the Light Affects Circadian Rhythms.” CDC, 1 May 2025, https://www.cdc.gov/niosh/work-hour-training-for-nurses/longhours/mod2/20.html.
Harvard Medical School. “Blue Light Has a Dark Side.” Harvard Health, 17 Apr. 2012, https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side.
National Eye Institute. “How the Eyes Work.” National Eye Institute, 20 Apr. 2022, https://www.nei.nih.gov/learn-about-eye-health/healthy-vision/how-eyes-work.
UC Davis Health. “Melatonin and Your Sleep: Is It Safe, What Are the Side Effects and How Does It Work?” UC Davis Health, 5 Feb. 2025, https://health.ucdavis.edu/blog/cultivating-health/melatonin-and-your-sleep-is-it-safe-what-are-the-side-effects-and-how-does-it-work/2025/02.
