Is Blue Light Actually Bad for You?

Learn how you can protect yourself from the effects of blue light.

Blue light is light of a certain wavelength that can be emitted or reflected by a variety of materials and surfaces in the world (Okuno et al., 2002). By its nature, blue light is damaging to the photoreceptors in the human retina. Some sources of blue light, such as the sun, certain metallic surfaces, and the sparks produced by metallurgy, give off so much blue light that it is highly damaging to look at them for more than a second or two (Okuno et al., 2002). Other sources, such as computer screens and fluorescent lights, emit lower concentrations of blue light, but still have the potential to harm our eyes.

When blue light reaches our skin, it causes DNA damage by interacting with the oxygen and nitrogen in our skin (Suitthimeathegorn et al., 2022) as well as by generating an inflammatory response in the skin. Our bodies react to the blue light by producing more melatonin, which can cause what is called hyperpigmentation, or the darkening of the skin, to occur. Over time, our unprotected skin can develop age spots, which are one manifestation of hyperpigmentation.

The melatonin reaction from blue light impacts not only our skin, but our state of mind as well. This bodily response in turn impacts our circadian rhythms (Suitthimeathegorn et al., 2022) –

the natural ebb and flow of energy in our bodies throughout the day, wherein we are more alert during the morning, then start to feel drowsy and naturally want to sleep in the evening. While exposure to blue light from sunlight is natural and can help us wake up, exposure to blue light when we want to be sleepy, such as late at night, can interrupt our bodies’ regulation of our wakefulness.

Blue Light and Sleep Exposure to blue light can and does mess with our sleep. Especially in modern society, where we struggle as a culture to put down our smartphones, tablets, and laptops, all of this blue light exposure is disturbing our natural circadian rhythms (Burgess & Molina, 2014). Just when we want to be feeling drowsy and tired, exposure to blue light makes us feel more alert, raises our body temperature, and raises our heart rate (Cajochen et al., 2005). All of that makes it harder to fall asleep.

So how do we avoid the negative effects of blue light? Thankfully, blue light-blocking glasses are both the subject of scientific study and are readily available from eyeglasses manufacturers everywhere. A recent review of studies showed that for all people, but especially those with sleep issues or related disorders, blue light-blocking glasses can reduce the negative impacts of exposure to blue light (Shechter et al., 2020). Beyond improvements in sleep, there is some evidence that wearing blue light-blocking glasses at work may also increase people’s work engagement and positive behaviors at work (Guarana et al., 2021).

Blue Light Therapy Believe it or not, some intentional blue light exposure can actually be beneficial. When it is judiciously applied, exposure to blue light can help in treating mental health and sleep disorders.

Blue Light Therapy for Seasonal Affective Disorder First up, we have treatment for seasonal affective disorder (SAD), or the phenomenon of getting depressed during the winter, when days are short and exposure to sunlight is reduced. Multiple studies now attest to morning exposure to blue light being an effective treatment for symptoms of SAD, as well as regular old “non-seasonal” depression (Maruani & Geoffroy, 2019). Thankfully, this treatment can take as little as one week to start having effects.

Blue Light Therapy for Performance Remember how blue light exposure increases our levels of alertness? It appears that intentional exposure to blue light can help us be especially alert when the situation calls for it. A couple studies indicate that even a single exposure to blue light positively impacts our performance on cognitive tasks (Killgore et al., 2020; Tonetti & Natale, 2019).

In Sum

The fact is – blue light isn’t going anywhere. Writing this article may have gotten you thinking about how to reduce exposure to blue light in your daily life. So what can you do to promote healthy sleep and skin? You could start by turning off the blue light on yourMacbook, especially after sundown. Turn down the brightness on your smartphone, try to make it a general priority to disengage from screens as much as possible after dinner. And most importantly, try to never use screens in bed, no matter how cozy it sounds to watch a movie from under the covers.

References

• ● Burgess, H. J., & Molina, T. A. (2014). Home lighting before usual bedtime impacts circadian timing: a field study. Photochemistry and Photobiology, 90(3), 723-726.

• ● Cajochen, C., Munch, M., Kobialka, S., Krauchi, K., Steiner, R., Oelhafen, P., ... & Wirz-Justice, A. (2005). High sensitivity of human melatonin, alertness, thermoregulation, and heart rate to short wavelength light. The Journal of Clinical Endocrinology & Metabolism, 90(3), 1311-1316.

• ● Guarana, C. L., Barnes, C. M., & Ong, W. J. (2021). The effects of blue-light filtration on sleep and work outcomes. Journal of Applied Psychology, 106(5), 784–796.

• ● Killgore, W. D., Dailey, N. S., Raikes, A. C., Vanuk, J. R., Taylor, E., & Alkozei, A. (2020). Blue light exposure enhances neural efficiency of the task positive network during a cognitive interference task. Neuroscience Letters, 735, 135242.

• ● Maruani, J., & Geoffroy, P. A. (2019). Bright light as a personalized precision treatment of mood disorders. Frontiers in Psychiatry, 10, 85.

• ● Okuno, T., Saito, H., & Ojima, J. (2002). Evaluation of blue-light hazards from various light sources. Developments in Ophthalmology, 35, 104-112.

• ● Shechter, A., Quispe, K. A., Mizhquiri Barbecho, J. S., Slater, C., & Falzon, L. (2020). Interventions to reduce short-wavelength (“blue”) light exposure at night and their effects on sleep: A systematic review and meta-analysis. Sleep Advances, 1(1), zpaa002.

• ● Suitthimeathegorn, O., Yang, C., Ma, Y., & Liu, W. (2022). Direct and indirect effects of blue light exposure on skin: A review of published literature. Skin Pharmacology and Physiology.

• ● Tonetti, L., & Natale, V. (2019). Effects of a single short exposure to blue light on cognitive performance. Chronobiology International, 36(5), 725-732.