Light has a powerful effect on your sleep because it controls your body’s internal clock, also known as the circadian rhythm. Exposure to light—especially blue light—can either help you fall asleep or keep you awake, depending on the timing and type of light you’re exposed to.
Light impacts sleep by influencing melatonin, the hormone that helps regulate sleep-wake cycles. When it’s dark, your brain produces more melatonin, making you feel sleepy. When it's light, melatonin production decreases, helping you feel alert and awake.
Exposure to morning sunlight helps reset your circadian rhythm.
It boosts serotonin, which later converts into melatonin at night.
Getting 15–30 minutes of daylight in the morning improves sleep quality at night.
Screens from phones, tablets, TVs, and LED lights emit blue light, which delays melatonin release.
Exposure to blue light within 1–2 hours before bed can cause:
Difficulty falling asleep
Poor sleep quality
Shortened REM sleep
Increased nighttime awakenings
Even small amounts of light—like a phone notification or hallway light—can send signals to your brain that it’s time to be alert.
This can result in:
Light sleep instead of deep, restorative sleep
Frequent wake-ups
Grogginess in the morning
Warm, dim lights are ideal before bed (think orange or red tones).
Avoid bright white or blue light 1–2 hours before sleep.
Consider using:
Blue light–blocking glasses
Night mode or dark mode on devices
Red-toned night lights for late-night bathroom trips
Get morning sunlight: Go outside or sit near a window after waking up.
Limit screen time before bed: Avoid devices at least 60 minutes before sleeping.
Use blackout curtains: Keep your bedroom completely dark.
Install dimmable lights: Create a calming evening routine.
Try smart bulbs: They adjust color temperature automatically based on time of day.
Light is one of the most important external factors affecting your sleep quality. Controlling your light exposure throughout the day and evening can help you fall asleep faster, stay asleep longer, and wake up more refreshed.
Why is blue light bad for sleep?
Does red light help you sleep better?
How much light is too much for sleep?
What are the best lights for a sleep-friendly bedroom?
This article is for informational purposes only and does not replace professional medical advice. Please consult a healthcare provider if you have chronic sleep issues.
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