9 Ways Our Bodies React to Changes in Lighting

Humans have a wide spectrum of reactions when it comes to light sources. If you’ve ever wondered how changes in color, intensity, or exposure can affect you, take a look at these 9 illuminating facts about the human body and its fascinating responses to light.

1. A TYPE OF SKIN CANCER CAN BE SENT PACKING.

Actinic (also known as solar) keratoses are bumpy, precancerous lesions that develop as a result of sun exposure, and approximately 10 percent of these growths can become squamous cell carcinoma if left untreated. To prevent that from happening, dermatologists look to blue light therapy. When the lesions are treated with a photosensitive chemical and exposed to the wavelength, oxygen radicals are created that destroy problematic precancerous and cancerous cells.

2. LIGHT CAN WAKE US UP.

Exposure to blue light can also help us feel more alert, according to one 2006 study. Study participants were divided into two groups, exposed to either blue or green light, and then asked to rate their energy levels. The subjects shown blue light described themselves as feeling more awake, and demonstrated quicker reaction times and longer attention spans than those exposed to green light.

3. IT CAN ALSO COMBAT SEASONAL AFFECTIVE DISORDER.

When the human eye is exposed to a bright light, cells in the retina connected to the hypothalamus region of the brain (which controls circadian rhythm) are stimulated. For people who suffer from Seasonal Affective Disorder (SAD), those rhythms can become disrupted once the days get shorter and there’s less sunlight to take advantage of. Artificial light exposure can help restore the balance, offering relief to people who experience symptoms of depression as a result of that disruption.

4. LIGHT MIGHT BOOST MEMORY.

Some exciting research is being done investigating how light-sensitive cells called ipRGCs and the melanopsin protein within can influence how our brains process information. In one study, subjects were shown blue, orange, or green light while they performed a memory assignment, then were asked to sit in the dark. After that, they did the memory test again, this time in green light. Those who viewed orange light first had more activity in their brains’ prefrontal regions—that’s the area associated with problem solving and complex thought processes—than the groups exposed to other colors.

5. TASK FOCUS GROWS SHARPER.

You might be surprised at how an increase in lumens (the measurement of light intensity) can affect your accuracy when it comes to focusing on tasks and fine motor control. One study indicated that pharmacists who used a light source with at least 1500 lux (measuring light concentration spread over a specific area) had an error rate of only 2.6 percent compared to the 450 lux group’s rate of 3.8 percent.

6. LIGHT EXPOSURE COULD BE A PAIN RELIEVER.

A 2005 study that compared hospital patients with varying exposures to sunlight found that those who received 46 percent more of the sun’s rays than those who were stationed away from hospital windows needed 22 percent less pain medication on an hourly basis than those who didn’t have as much access to light.

7. WE PROCESS MORE VITAMIN D.

While sunlight is a common source for this valuable vitamin, our bodies may be able to metabolize it with help from exposure to artificial light containing UV radiation as well. The finding may be beneficial to shift workers or those who have only limited access to sunlight.

8. RED LIGHT CAN HELP US SLEEP.

Warmer lighting, as opposed to blue light, tends to be less effective at suppressing melatonin production, which allows us to settle into a more routine sleep/wake cycle. Ensuring your night lights are dim, red bulbs could improve your rest.

9. WE EVEN REACT TO LIGHT THAT ISN’T THERE.

In 2012, scientists discovered a peculiar quirk of our pupils: They’ll constrict when presented with graphic designs that give off the appearance of having a bright center, even when no actual light is being transmitted into the eye. The illusory perception may be part of our bodies’ efforts to protect us from exceptionally bright light sources. Whatever the reason, it’s clear we have a relationship with light that continues to be surprising.