Have you ever woken up in the middle of the night, feeling oddly alert? Or struggled to fall asleep, even when you're tired? The culprit might not be your caffeine intake or stress—it could be the tiny, seemingly harmless lights in your bedroom.
Most people know that bright overhead lights or phone screens before bed can mess with sleep, but even the smallest light sources can trick your brain into thinking it's still daytime.
Let’s dive into the unexpected ways light could be disturbing your sleep—and the science behind it.
1. Your Alarm Clock’s Glow Is Messing with Melatonin
Many alarm clocks have a bright digital display that glows all night long. The problem? Even dim artificial light can suppress melatonin production—the hormone responsible for making you feel sleepy.
📌 The Science: A 2011 study in the Journal of Clinical Endocrinology & Metabolism found that exposure to dim light before bedtime can reduce melatonin levels by up to 50%. This means your body isn’t properly preparing for deep sleep.
✅ Fix It: Swap your glowing alarm clock for one with a dimmable red light (red wavelengths have the least impact on melatonin). Or better yet, place your alarm clock facing away from you or under a cloth.
2. The Tiny LED Indicators Around Your Room
Power buttons, chargers, WiFi routers, and TVs often have small LED lights that stay on all night. They seem harmless, but your brain detects even low levels of light, which can impact your sleep quality.
📌 The Science: A Harvard study found that nighttime exposure to blue and green light wavelengths (like those from LED lights) can shift circadian rhythms and delay sleep onset.
✅ Fix It: Cover LEDs with electrical tape, unplug devices overnight, or use a blackout sleep mask if eliminating all light isn’t an option.
3. Streetlights and Passing Headlights—A Major Sleep Disruptor
Before installing blackout blinds, I didn’t realise just how much car headlights sweeping through my window were disturbing my sleep. Streetlights, security lights, and even the glow from a neighbour’s porch light can filter through regular curtains and keep your brain from fully settling into deep sleep.
📌 The Science: Studies show that even low levels of artificial light at night can increase nighttime wakefulness and reduce REM sleep. In fact, a study in JAMA Internal Medicine found that people exposed to outdoor artificial light had a higher risk of insomnia and even weight gain.
✅ Fix It: Install blackout blinds (like Mahalo Eco Blinds!) to block out external light completely. If that’s not possible, try layering blackout curtains over your blinds for extra coverage.
4. Your Bathroom Light Wakes You Up More Than You Realise
Getting up to use the bathroom in the middle of the night? If you switch on a bright overhead light, it can instantly disrupt melatonin and signal to your body that it’s morning—making it much harder to fall back asleep.
📌 The Science: Research from the University of Basel found that exposure to bright white light for just 5 minutes at night can shift your circadian rhythm and make falling back asleep harder.
✅ Fix It: Use a low-wattage, warm-coloured nightlight in the bathroom instead of turning on the main light. Red or amber lights are the best option since they have minimal impact on melatonin.
5. What About Moonlight? The Full Moon & Sleep Sensitivity
You might have heard that moonlight doesn’t suppress melatonin like artificial light does—and that’s true! Unlike LED or fluorescent light, moonlight is simply reflected sunlight that has been scattered and softened, making it much weaker in intensity.
📌 The Science: Studies have shown that the colour temperature and brightness of moonlight are not strong enough to significantly impact melatonin production. This means, in theory, the moon shouldn’t interfere with sleep like artificial lights do.
✅ But here’s the catch: If you’re extra sensitive to light (like me), you may still find that a bright full moon streaming through your window keeps you awake. This isn’t necessarily because of melatonin suppression but rather because your body senses the change in brightness—especially if your room is usually dark.
🌕 The Full Moon Effect: Some research suggests people take longer to fall asleep and experience less deep sleep around the full moon. While the exact reason isn’t clear, it could be due to the increased brightness or even an evolutionary response.
✅ Fix It: If moonlight disturbs your sleep, blackout blinds are the best solution. They allow you to control your sleep environment and keep your room consistently dark—no matter what phase the moon is in.
The Bottom Line: Light Matters More Than You Think
Even small amounts of light can mess with your sleep by suppressing melatonin, shifting your circadian rhythm, and causing unnecessary wake-ups. But the good news? Small tweaks can make a huge difference in how well you sleep.
