For years, digital screens have been blamed for sabotaging sleep, but new evidence suggests the issue is far more complex than the glow of a smartphone.

In an effort to test the theory, I spent several weeks adopting an extreme nighttime routine. Three hours before bed, I wore bulky orange-tinted goggles designed to block blue wavelengths, turned off artificial lighting, sealed windows with blackout curtains and relied solely on candlelight. The regimen was uncomfortable and impractical, but it offered a firsthand look at what happens when blue light is eliminated.

Public concern over blue light has intensified over the past decade, driven by claims that devices such as phones, televisions and LED bulbs emit levels that disrupt the body’s internal clock. While some scientific evidence supports this, recent analyses indicate the relationship between light exposure and sleep is more nuanced. Specialists say it is unlikely that screen light alone is the primary cause of poor sleep.

Findings remain inconsistent. Features intended to reduce blue light on devices appear to have minimal effect on sleep quality. However, broader patterns of light exposure in modern life can significantly influence rest. Understanding how to adjust those patterns may be key.

Seeking clarity, I consulted researchers and reviewed the science while subjecting myself to evenings almost entirely free of blue light. The result was a set of practical insights that do not require extreme measures like tinted goggles but may still improve sleep.

Early Research Sparked Alarm

Concerns about blue light gained traction after a 2014 study comparing bedtime reading habits. Participants who used an iPad took longer to fall asleep, felt more fatigued the next day and produced less melatonin than those reading printed books. Researchers attributed the difference to LED screens, which emit higher levels of blue-spectrum light known to affect circadian rhythms — the body’s natural timing system.

Subsequent studies appeared to support those conclusions, but experts caution against oversimplification.

"This was an incredibly deceptive piece of work," says Jamie Zeitzer, a professor of psychiatry and behavioural sciences at Stanford University, who studies the effect of light on the circadian system. The science wasn't bad, he says, the problem is it brought people to bad conclusions.

Modern screens do emit more blue light because of how LEDs produce white light — by combining blue light with yellow phosphor. This process allows excess blue wavelengths to persist. Blue light can influence sleep because of melanopsin, a light-sensitive protein in the eye.

"And melanopsin is a blue sensitive protein, which basically means that it is most sensitive to blue light," he says. Melanopsin reacts to other colours of light too, the effect of blue is just a bit stronger.

Still, researchers emphasize that the intensity of light from screens is relatively low.

"But the amount of light emitted from our screens is really inconsequential," says Zeitzer. Laboratory studies often expose participants to unusually dim conditions before introducing bright light, exaggerating the effect compared to real-life environments.

More recent reviews suggest screens delay sleep by only a few minutes on average. Meanwhile, the blue light received from digital devices over an entire day is negligible compared to even brief exposure to natural sunlight. Some studies indicate it is insufficient to significantly alter hormone levels tied to sleep.

Lifestyle, Not Screens, Drives Sleep Problems

Experts say the broader issue lies in daily light exposure patterns. To maintain healthy sleep, the body needs strong light signals during the day and reduced exposure at night.

My experiment reflected this principle. Each morning, I sat close to a high-intensity light lamp designed to treat seasonal depression, exposing myself to bright, blue-rich light early in the day. The experience was unpleasant but reinforced a key concept.

"The more light that you get during the daytime, the less impact the light in the evening has," Zeitzer says.

Modern routines often limit daytime light exposure. Remote work, indoor lifestyles and reduced commuting mean many people experience similar lighting conditions from morning to night, blurring the distinction between day and evening for the body’s internal clock.

Outdoor light remains far more powerful than indoor sources. Even on cloudy days, natural light far exceeds typical indoor lighting levels. A short morning walk can help regulate circadian rhythms, while additional afternoon exposure may further stabilize sleep patterns.

"Go outside if you can, use the lamp if you have to," says Håvard Kallestad, director of the sleep and chronobiology research group at the Norwegian University of Science and Technology.

Another recommendation is to increase lighting during the day and gradually dim it in the evening. Creating contrast between day and night conditions appears to be more important than eliminating blue light entirely.

Behavior Matters More Than Light

While screens may play a role, experts argue their impact is often indirect. The activities people engage in before bed — such as scrolling social media or consuming stimulating content — may be more disruptive than the light itself.

"It is much more the content, rather than the light, that is keeping people awake from these devices," Zeitzer says.

Individual sensitivity to light also varies, meaning some people may be more affected than others.

Subtle Gains From Extreme Measures

Using a sleep tracker, I monitored the effects of my blue-light-free routine. Overall sleep duration remained largely unchanged, but I noticed improved consistency in when I fell asleep and woke up. By the second week, going to bed felt easier, though it is unclear whether this was due to reduced blue light or the structured routine itself.

The ritual of dimming lights and using candles may have played a psychological role.

When something "becomes part of the pre-bed process, it can act as a very strong psychological cue to help remind your body of what you're supposed to be doing next", Zeitzer says.

Similarly, device features that shift screen color at night may work less through biological effects and more by signaling bedtime.

"It doesn't really work that well, but the one thing that it can do is that when you have one of these filters, or if you wear blue blocking glasses in the evening, is that acts as kind of like a Pavlovian conditioning cue for some people. When the screen colour changes, or you put on your glasses, your brain starts to understand it is time to get ready for bed."

A Simpler Approach to Better Sleep

Despite the extreme nature of the experiment, the takeaway was straightforward: improving sleep does not require eliminating blue light entirely. Instead, maintaining strong daytime light exposure, reducing brightness at night and establishing consistent bedtime habits may be more effective.

While the goggles have been retired, one change may remain — evenings lit by candles, not as a necessity, but as a calming signal that it is time to rest.