In this episode, I host Dr. Samer Hattar, Ph.D., Chief of the Section on Light and Circadian Rhythms at the National Institute of Mental Health. Dr. Hattar is a world-renowned expert on how viewing light at particular times adjusts our mood, ability to learn, stress and hormone levels, appetite, and mental health. We discuss how to determine and use your individual light sensitivity to determine the optimal sleep-wake cycle for you. We also discuss how to combine your light viewing and waking time with the timing of your food intake and exercise in order to maximize mental and physical functioning. Dr. Hattar is credited with co-discovering the neurons in the eye that set our circadian clocks and regulate mood and appetite. He explains why even a small shift in daylight savings leads to outsized effects on our biking because of the way that our cells and circadian clocks integrate across many days. And he offers precise tools to rapidly adjust to jet lag, shift work, and reset your clock after a late night of work or socializing. This episode is filled with cutting-edge data on the biological mechanisms of human physiology and practical tools for people of all ages.

Read the full show notes for this episode at hubermanlab.com.

Thank you to our sponsors

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Timestamps

00:00:00 Introducing Dr. Samer Hattar, Ph.D.

00:02:33 Sponsors: AG1, LMNT & Waking Up

00:06:15 Light, Circadian (24-hour) & Circannual (365-day) “Photoentrainment”

00:14:30 Neurons in Our Eyes That Set Our Body Clocks: Similar to Frog Skin

00:18:55 What Blind People See

00:20:15 When, How & How Long to View Light for Optimal Sleep & Wakefulness

00:30:20 Sunlight Simulators, Afternoon Light Viewing, Naps

00:33:48 Are You Jet Lagged at Home? Chronotypes & Why Early Risers Succeed

00:38:33 How to Decide Your Best Sleep-Wake Schedule; Minimal Light Test

00:42:16 Viewing Light in Middle of Day: Mood & “Light Hunger”

00:44:55 Evening Sunlight; Blueblocker Warning

00:48:57 Blue Light Is Not the Issue; Samer’s Cave; Complete Darkness

00:53:58 Screens at Night

00:56:03 Dangers of Bright Light Between 10 pm and 4 am: Mood & Learning

01:01:05 The Tripartite Model: Circadian, Sleep Drive, Feeding Schedules

01:05:05 Using Light to Enhance Your Mood; & The Hattar-Hernandez Nucleus

01:07:19 Why Do We Sleep?

01:08:17 Effects of Light on Appetite; Regular Light & Meal Times

01:18:08 Samer’s Experience with Adjusting Meal Timing

01:22:51 Using Light to Align Sleep, Mood, Feeding, Exercise & Cognition

01:30:15 Age-Related Changes in Timing of Mental & Physical Vigor

01:31:44 “Chrono-Attraction” in Relationships; Social-Rhythms

01:33:40 Re-setting Our Clock Schedule; Screen Devices Revisited

01:37:50 How Samer Got into the Study of Light

01:39:33 Clock Gene mRNAs & More Accurate Biomarkers

01:41:08 Light as Medicine

01:42:48 ADHD (Attention-Deficit Hyperactivity Disorder)

01:43:35 How to Beat Jet Lag: Light, Temperature, Eating

01:50:44 Vigor: The Consequence of Proper Timing

01:52:15 Waking in the Middle of the Night: When Your Nightly Sleep Becomes a Nap

01:54:10 Melatonin, Pineal Calcification

01:55:25 Our Seasonal Rhythms: Mood, Depression, Lethargy & Reproduction

01:59:08 Daylight Savings: Much Worse Than It Might Seem

02:05:27 Eye Color & Sensitivity to Light, Bipolar Disorder

02:09:28 Spicy Food, Genetic Variations in Sensory Sensitivity

02:10:52 Synthesizing This Information, Samer on Twitter, Instagram

02:13:00 Conclusions, Ways To Support the Huberman Lab Podcast & Research

Disclaimer & Disclosures

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