Podcast transcript:

Hello and Welcome to News From The Future, spoken by the eleven labs audio clone of Dr Catherine Ball.

In this new short series we will be focussing on Sleep. We all do it, and we all recognise when we have not had enough of it.

Dr Cath’s new book The Future of Sleep is out now and available globally in paperback, audiobook, and ebook formats.

We think you’ll get something life changing from it.

Today we are talking about something a bit controversial - Blue Light

Enjoy!

For over a decade, warnings about blue light from our screens have dominated conversations about poor sleep. The narrative is simple: the blue glow of our devices disrupts our circadian rhythm, delaying sleep and leaving us groggy the next day. However, Hana Mendel’s deep dive into the science behind these claims reveals that the story is far more nuanced. The issue isn’t just about blue light—it’s about how modern life, in its entirety, disrupts our exposure to light and dark. Let’s unpack the details of her findings.

The blue light panic began in 2014 with a small study that compared participants reading on an iPad before bed to those reading physical books. The iPad users took longer to fall asleep, produced less melatonin (a hormone critical for sleep), and felt more tired the next day. Researchers attributed these results to the blue-enriched light emitted by the iPad, which mimics daylight and interferes with our body’s natural clock. The study launched a wave of concern about blue light, with many people blaming their phones, tablets, and TVs for their sleepless nights.

But experts like Jamie Zeitzer, a professor of psychiatry and behavioral sciences at Stanford University, caution against oversimplifying the issue. While it’s true that blue light can affect sleep, the light emitted by our screens is minimal compared to other sources. Modern screens and LED light bulbs do emit more blue light than older technologies because they use blue LEDs coated with yellow phosphor to simulate white light. But the amount of blue light from these devices is trivial compared to the blue light we receive from the Sun. One study found that 24 hours of exposure to screens amounts to less than one minute of sunlight exposure. Another review of 11 studies showed that screen light delays sleep by just nine minutes at worst—not exactly the catastrophic impact many fear.

So, if blue light from screens isn’t the main culprit, what is? Mendel’s exploration points to a broader issue: the way modern lighting and lifestyles disrupt our natural exposure to light and dark. Our bodies are designed to respond to the contrast between bright daylight and dim evenings, but many of us spend our days indoors under artificial light that’s far dimmer than natural sunlight. This lack of exposure to bright light during the day makes us more sensitive to light at night, whether it’s blue or not.

To test these ideas, Mendel embarked on an extreme experiment to eliminate blue light from her evenings. She wore industrial-grade orange goggles designed to block blue light completely, covered her windows with blackout curtains, and replaced all her lamps with candles. While effective, the goggles were impractical and uncomfortable—better suited for industrial work than everyday life. The candlelit evenings, however, became a calming ritual that Mendel grew to appreciate.

Experts like Håvard Kallestad, a sleep researcher, emphasize that avoiding blue light at night is only part of the solution. The real key is managing your total light exposure throughout the day. Bright light in the morning, especially light that’s rich in blue wavelengths, helps regulate your circadian rhythm and makes your body less sensitive to light in the evening. Mendel experimented with a bright light therapy lamp each morning, designed to treat seasonal depression. While sitting in front of the lamp wasn’t particularly enjoyable, it helped anchor her body clock.

Zeitzer highlights the importance of contrast in light exposure. During the day, brighter lighting signals to your body that it’s daytime. In the evening, gradually dimming your lights helps cue your body to start winding down. Even a 30-minute walk outside in the morning can make a significant difference, as natural sunlight is far more intense than indoor lighting. On a cloudy day, outdoor light intensity can reach 10,000 lux, while a sunny day can hit 100,000 lux. In contrast, indoor lighting typically measures around 100 lux, and your phone emits only 50-80 lux at full brightness.

Interestingly, the content we consume on our devices may be more disruptive to sleep than the light itself. Engaging in stimulating activities like scrolling through social media or watching intense shows can keep your brain alert, making it harder to fall asleep. This suggests that what we do on our screens matters more than the light they emit.

Mendel’s experiment didn’t dramatically improve her sleep quality, but it did lead to some positive changes. By the end of her two-week trial, she found it easier to fall asleep and wake up at consistent times. The psychological cues from her candlelit evenings and other bedtime rituals seemed to help her body recognize when it was time to wind down. This aligns with Zeitzer’s observation that such routines can act as “Pavlovian conditioning” for sleep, signaling to your brain that bedtime is approaching.

While blue light isn’t entirely blameless, it’s not the sleep saboteur it’s often made out to be. The real issue is our overall exposure to light and how it aligns with our natural rhythms. To improve your sleep, focus on getting plenty of natural light during the day, dimming your lights in the evening, and creating calming bedtime rituals. If you’re tempted to try blue-blocking glasses or phone filters, know that their biggest benefit might be the psychological signal they send to your brain that it’s time to unwind.

Mendel’s findings highlight the complexities of light’s impact on sleep and the importance of looking beyond simple solutions. While you probably won’t be rushing to stock up on candles or orange goggles, her experiment offers practical advice for anyone looking to improve their sleep in a world that’s increasingly lit up 24/7.

Please share this podcast with anyone you know who sleeps.

Thank you for supporting my work. Please follow me on LinkedIn or subscribe to my substack for more News From The Future

And please buy my book: The Future of Sleep.

Thank you.

Thanks for reading "News From The Future" with Dr Catherine Ball! This post is public so feel free to share it with anyone who sleeps.

This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drcatherineball.substack.com/subscribe