I have a question about this episode Using Light (Sunlight, Blue Light & Red Light) to Optimize Health | Huberman Lab Podcast #68 and this Light and Mood Why should you not watch artificial light between 10 PM and 4 AM as discussed in the episode Science-Based Tools for Increasing Happiness | Huberman Lab Podcast #98 and the clip Light Exposure Strategies?

Avoiding bright artificial light between 10 PM and 4 AM is crucial for maintaining healthy mood and cognitive function. According to Andrew Huberman, exposure to bright lights during these hours can negatively impact dopamine circuits in the brain, which are associated with mood regulation and can lead to feelings of depression 1.

Specifically, he mentions that bright light exposure during these late-night hours disrupts melatonin production, the hormone that induces sleepiness. Viewing bright light for just 15 seconds can profoundly lower melatonin levels, making it harder to fall asleep and stay asleep 2. Furthermore, studies have shown that bright light exposure between 10 PM and 4 AM can also inhibit learning and memory, as well as disrupt overall immune function 3.

To mitigate some of the negative effects of late-night light exposure, Huberman suggests getting sunlight or bright natural light in the late afternoon or evening, which can help buffer against the detrimental effects of bright lights later at night 4. This practice can maintain melatonin rhythms and support mood stability, emphasizing the importance of managing light exposure strategically throughout the day and night.