Why is bright light at night bad for sleep?

Bright light at night is detrimental to sleep for several reasons, as explained by Andrew Huberman on the Huberman Lab. The primary issues include:

• Bright light at night suppresses melatonin release, which is essential for inducing sleepiness and transitioning into sleep 1.
• Even low light levels after 8 PM can reset and shift the body's circadian clock, which is why it is advised to avoid bright light especially between 10 PM and 4 AM 2.
• Exposure to bright light in the middle of the night suppresses dopamine release, impacting mood and potentially altering learning and attention processes 3 4.
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    1

    Optimize Your Sleep

    01:00:56
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    2

    Light and Circadian Rhythm

    00:15:13
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    3

    Light and Hormones

    01:02:13
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    4

    Light and Mood

    00:48:27
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    5

    Sleep and Myopia

    00:59:19
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    6

    Light and Sleep

    00:06:27
• Studies have shown that bright light exposure between 10 PM and 4 AM can disrupt mood-producing systems in the brain and have negative effects on health and learning 5 6.

Therefore, it is essential to manage the timing and intensity of light exposure to improve sleep quality and support overall well-being.