In this Huberman Lab Essentials episode, my guest is Dr. Samer Hattar, PhD, the Chief of the Section on Light and Circadian Rhythms at the National Institute of Mental Health.We discuss how light powerfully shapes mood, sleep, appetite, learning and overall mental health by aligning—or misaligning—our internal circadian clock. We explain practical protocols to support your circadian rhythm, including morning sunlight exposure, dim evening lighting and regular mealtimes. We also discuss strategies to manage jet lag, limit evening screen use, ease seasonal depression and improve focus by syncing light, sleep and food with natural biological rhythms.Read the episode show notes at hubermanlab.com.Thank you to our sponsorsAG1: https://drinkag1.com/hubermanEight Sleep: https://eightsleep.com/hubermanROKA: https://roka.com/hubermanTimestamps(00:00) Samer Hattar(00:27) Light, Circadian Clock vs Solar Day, Sleep-Wake Cycle(03:20) Eyes, Photoreceptors & Light Entrainment, Blindness, Sleep(06:13) Morning Light, Artificial Lights, Tool: Morning Sunlight Exposure(08:28) Jet Lag Without Traveling, Sleep Issues, Screens, Staying Indoors(09:19) Sponsors: Eight Sleep & ROKA(12:14) Chronotypes, Intrinsic Circadian Rhythms(14:06) Afternoon & Evening Light, Tools: Dimming Lights, Reduce Screen Use(15:57) Light Exposure & Effects on Stress, Mood & Learning, Tripartite Model(19:30) Light & Appetite, Tool: Regular Meal Times(22:39) Using Light to Improve Sleep, Mood & Mental Health(24:20) Sponsor: AG1(25:42) Jet Lag, Tools: Temperature Minimum; Eat on Local Schedule, Avoid Mismatched Light Exposure(29:15) Sleep Issues, Light-Dark Cycle(30:50) Seasonality, Seasonal Depression; Daylight Savings Time(34:07) AcknowledgementsDisclaimer & DisclosuresLearn more about your ad choices. Visit megaphone.fm/adchoices