Why is bright light at night bad for sleep?


Bright light at night is detrimental to sleep because it disrupts the natural release of melatonin, a hormone that facilitates sleepiness and helps regulate the sleep-wake cycle. highlights that exposure to bright, particularly overhead, artificial lights between 10:00 p.m. and 4:00 a.m. can mimic sunlight and negatively affect sleep quality and the ability to fall and stay asleep. It's important to minimize bright light exposure during these hours, using only necessary light to perform tasks safely 1.

Additionally, light exposure at night, including from digital screens, can suppress the release of dopamine, which may lead to lower mood and affect, further disrupting sleep patterns 2. To counteract these effects, it's advised to dim artificial lights as much as possible and ideally avoid bright light exposure altogether during the critical hours before sleep 2.

Moreover, blue light exposure, even through closed eyelids, can impact the secretion of melatonin and other mood-related neurotransmitters. Using bright light inappropriately at night not only affects sleep but can also have detrimental effects on one's mood, learning, immunity, and even blood sugar levels 3.

Optimize Your Sleep

Andrew explains the importance of avoiding bright artificial lights between 10:00 p.m. and 4:00 a.m. to improve sleep quality. He also recommends using low lights at night and bright artificial lights during the day to optimize sleep-wake cycles. Additionally, viewing evening sunset light can offset some of the negative effects of artificial light at night.

Huberman Lab

Sleep Toolkit: Tools for Optimizing Sleep & Sleep-Wake Timing | Huberman Lab Podcast #84

For optimal sleep, it's recommended to expose oneself to bright natural or artificial light in the morning and throughout the day, and conversely, avoid exposure to bright light at nighttime 2.