Does the blue light from nighttime scrolling really prevent you from sleeping?

[WORLD] Struggling to fall asleep? It's easy to blame your phone, which is only inches away from your face, and the never-ending newsfeed that your thumb is scrolling through while you lie in bed. However, the concept that the blue light emitted by your smartphone is causing you distress is incorrect.

While blue or short-wavelength light (such as daylight or light generated by technology) has an impact on our circadian rhythm, the situation is more complicated than we generally believe.

Recent studies have shown that the relationship between blue light and sleep disturbances is not as straightforward as previously thought. Researchers from the University of Manchester conducted experiments on mice and found that warm, yellow lights may actually be more disruptive to sleep patterns than cool, blue lights. This challenges the conventional wisdom about blue light's effects on sleep and suggests that the intensity and timing of light exposure may be more critical factors.

"Sleep is a complex process," explains Stuart Peirson, Oxford University's professor of circadian neurology.

He says that, although cells that absorb blue light activate the receptors in our eyes that notify our brain when it's time to wake up, cells that absorb longer wavelengths of light (such as red) do as well. This suggests that the problem isn't the color of the light, but rather the brightness and duration of exposure - yet our phone screens are really rather dull.

It's worth noting that our bodies have evolved to respond to natural light cycles, with blue light being prevalent during the day and warmer tones dominating during sunset and evening hours. This natural progression of light helps regulate our internal clock. However, the artificial light from our devices doesn't follow this pattern, potentially leading to confusion in our circadian rhythms. This misalignment between our internal clock and external cues could contribute to sleep difficulties more than the specific color of light emitted by our devices.

Daylight is 1,000 times brighter than the light emitted by the typical phone. Room illumination is, on average, ten times brighter. (This is why turning off the huge light as you wind down in the evening might make you feel more sleepy.)

"Technically, blue light from smartphones can affect sleep," according to Peirson. "But these effects are small unless you are using your phone for hours with a bright screen and already have sleep problems." In lab trials at Harvard University, even four hours of full-power light exposure from an e-reader showed just a little effect: a 10-minute delay in sleep onset. Indeed, the types of information you consume have a greater impact on your sleep.

Experts emphasize that the content we engage with on our devices may play a more significant role in sleep disturbances than the light itself. Dr. Lisa Meltzer, a sleep psychologist at National Jewish Health, points out that engaging in work-related activities, scrolling through social media, or consuming anxiety-inducing news before bedtime can increase cognitive arousal and make it harder to fall asleep. These activities can trigger stress responses and keep our minds active when we should be winding down.

If you believe light is affecting your sleep, Peirson says you don't need to spend money on special "blue-light blocking" spectacles. Instead, he suggests limiting your screen time and lowering the brightness on your phone.

While the debate about blue light continues, sleep experts agree that maintaining good sleep hygiene is crucial for quality rest. This includes establishing a consistent sleep schedule, creating a relaxing bedtime routine, and ensuring a comfortable sleep environment. Dr. Michael Grandner, director of the Sleep and Health Research Program at the University of Arizona, recommends a "digital sunset" - gradually reducing screen time and dimming lights in the hours leading up to bedtime. This approach can help signal to your body that it's time to prepare for sleep, regardless of the specific type of light you've been exposed to throughout the day.