Huberman Lab
Journal Club with Dr. Peter Attia | Effects of Light & Dark on Mental Health & Treatments for Cancer
Julian Elve's AI podcast notes AI-generated based on their snips
AI-generated based on their snips
1. Light exposure during the morning and daytime, as well as dark exposure at night, have independent and positive effects on mental health and can reduce symptoms of mental health disorders
2. The paper examined light exposure behavior as well as dark exposure behavior in a cohort of more than 85,000 people in the UK. There is a relationship between light and mental health and physical health. Giving people exposure to bright light in the morning is a treatment for seasonal affective disorder
3. Both daytime light exposure and nighttime dark exposure have been found to play a significant role in mental health. Intrinsically photosensitive retinal ganglion cells in the neural retina respond to two types of light input and send information to the hypothalamus. The hypothalamus, where the master circadian clock resides, sends out secretory signals based on the information received from retinal ganglion cells
4. Melanopsin cells respond to two different types of light input and send information to the hypothalamus where the circadian clock resides. The circadian clock sends out secretory signals and neural signals to regulate wakefulness and sleep. Melanopsin cells also project to brain areas that control mood and neurotransmitter release
5. If you're out in the sun with no cloud cover or minimal cloud cover in the middle of the day at noon, it can be over 100,000 lux. Most indoor environments are not as bright as they seem, with maximum lux levels of around 6,000. On a cloudy day, it can still be as bright as an average of 100,000 lux, even though the sun might not be visible. Cloud cover filters out long wavelength light, making it seem less bright, but the circadian clock still responds to the sum of photons
6. Indoor lighting with large windows may not provide sufficient sunlight unless the light comes directly through the window. Skylights on the roof can significantly improve the situation by allowing the neurons in the eye to gather light from above, which is crucial for signaling to the circadian clock and mood centers in the brain. These neurons primarily reside in the bottom two thirds of the neural retina and are responsible for perceiving ambient light, making this mechanism highly conserved in cellular organisms
7. Exposing oneself to low solar angle sunlight both in the morning and the evening helps in stabilizing the circadian clock by balancing the signals received from photo pigments. This practice prevents drifting of sleep-wake cycles. Midday sun, while beneficial for mood and well-being, does not affect the circadian clock due to its placement in the circadian dead zone
