Your body runs on a 24-hour clock whether you respect it or not, and the guests below are the people who actually study that clock for a living. We pulled these picks from our full library of episode summaries, favoring conversations that hand you a mechanism you can act on today rather than another generic reminder to 'get sunlight.'
Expect deep dives on why regularity might matter more than duration, how a single hour of morning light can move your cortisol curve, what time-restricted eating really does to a mouse's lifespan, and why the person most obsessed with fixing your sleep might be making it worse. Start wherever your own problem is: mistimed meals, 3AM wakeups, burnout, or just wanting to understand the biology behind the advice.
World No.1 Sleep Expert: Magnesium Isn’t Helping You Sleep! This Habit Increases Heart Disease 57%!
Walker returns with research that overturns some of his own earlier advice, including new evidence that sleep can be 'banked' before a stretch of deprivation and that regularity now beats total sleep quantity at predicting mortality. He also dismantles the blue-light panic and shows melatonin supplements barely outperform placebo. Anyone who's been chasing eight hours on a schedule should hear why consistency is the number that actually matters.
Read the full episode notesIntermittent Fasting to Improve Health, Cognition & Longevity | Dr. Satchin Panda
The Salk Institute's circadian pioneer separates caloric restriction from meal timing, citing mouse studies where the same calories eaten in the active phase pushed lifespan gains from 10% to 35%. He also connects daylight saving time's spring-forward shift to a documented spike in heart attacks and car accidents. Essential listening for anyone experimenting with an eating window and wondering if the clock matters as much as the calories.
Read the full episode notesDr. Andrew Huberman — A Neurobiologist on Sleep, Performance, and Anxiety | The Tim Ferriss Show
Huberman lays out his personal light-and-breathing toolkit, from viewing sunlight within minutes of waking to trigger a healthy cortisol pulse, to his exact nighttime supplement stack of apigenin, magnesium, and theanine. He explains why he skips melatonin entirely, since it can suppress the reproductive hormone axis at typical supplement doses. A strong starting point for anyone who wants the full protocol in one sitting.
Read the full episode notesUse Sleep to Enhance Learning, Memory & Emotional State | Dr. Gina Poe
UCLA's Gina Poe explains why going to bed later than usual means missing the first-cycle bolus of growth hormone for good, since your circadian clock has already moved on. She also flags consistent bedtimes as one of the best markers of healthy brain aging, not just total hours. Listen if you've ever assumed a late night could simply be made up later.
Read the full episode notesDr. Matt Walker: The Biology of Sleep & Your Unique Sleep Needs | Huberman Lab Guest Series
The opening episode of the six-part Huberman-Walker sleep series covers the 90-minute non-REM/REM architecture and debunks the popular gadget trend of timing wake-ups to cycle boundaries. Walker cites a UCLA study where a single night of four-hour sleep cut natural killer cell activity by 70%. A solid foundation episode for listeners who want the biology before the hacks.
Read the full episode notesThe Science of Vision, Eye Health & Seeing Better
Huberman separates the conscious eyesight system from the subconscious melanopsin cells that set your circadian clock, arguing the earliest eye cells evolved to tell the body what time it is, not to see shapes. He cites clinical trials showing two hours of daily outdoor light without sunglasses meaningfully cuts myopia risk. Good for listeners who want to understand why morning light works, not just that it does.
Read the full episode notesDr. Matt Walker: Protocols to Improve Your Sleep | Huberman Lab Guest Series
This installment of the guest series walks through five core sleep-hygiene levers, regularity, light and darkness, temperature, getting out of bed when awake, and limiting alcohol and caffeine. Walker notes that as little as 15 seconds of bright light in the evening can suppress melatonin, and that his counterintuitive rule after a bad night is to do nothing differently at all. A practical follow-up for anyone who wants the checklist version.
Read the full episode notesThe Science & Practice of Perfecting Your Sleep | Dr. Matt Walker
Walker walks through what caffeine, alcohol, THC, CBD, magnesium, and melatonin actually do to sleep architecture, tempering some of his own earlier alarmist framing. He cites a Harvard analysis finding REM sleep is the single strongest linear predictor of longevity, with every 5% drop linked to roughly 13% higher mortality risk. Recommended for anyone deciding whether a nightly glass of wine or a melatonin gummy is worth it.
Read the full episode notesOptimize & Control Your Brain Chemistry to Improve Health & Performance | Huberman Lab Podcast #80
A solo deep-dive arguing that dopamine, epinephrine, serotonin, and acetylcholine sit behind nearly every sleep, focus, and mood protocol, and that each shifts across three phases of the 24-hour day. Huberman names deliberate cold exposure as the single most potent tool for sustained dopamine increases. Best for listeners who want the underlying chemistry connecting circadian timing to daily performance.
Read the full episode notesHow to Control Your Cortisol & Overcome Burnout
Huberman reframes cortisol as an energy-deploying hormone rather than a pure stress signal, and centers the episode on getting its 24-hour rhythm right: high in the morning, low at night. He notes that bright light in the eyes within the first hour of waking can boost cortisol by up to 50%. Anyone dealing with burnout or feeling 'wired and tired' should start here.
Read the full episode notesUsing Light (Sunlight, Blue Light & Red Light) to Optimize Health | Huberman Lab Essentials
This Essentials episode breaks down how specific wavelengths of light regulate melatonin, testosterone, estrogen, and immune function, and why endogenous melatonin behaves nothing like the supplement version. Huberman explains melatonin's role as a calendar hormone, released more in winter than summer, and warns that flipping on a bright bathroom light at night can crash nighttime melatonin almost instantly. Useful for listeners who want the light-exposure rules in one condensed pass.
Read the full episode notesDr. Matt Walker: Improve Sleep to Boost Mood & Emotional Regulation | Huberman Lab Guest Series
Walker and Huberman detail how sleep deprivation causes a 60% jump in amygdala reactivity while severing prefrontal control, and how REM sleep works like overnight therapy that strips the emotional charge from memories. Walker notes that in 20 years of research, no psychiatric condition has ever been found where sleep is normal. A vital episode for anyone connecting a bad sleep schedule to anxiety or low mood.
Read the full episode notesJournal Club with Dr. Peter Attia | Effects of Light & Dark on Mental Health & Treatments for Cancer
Huberman presents a Nature Mental Health study of over 85,000 UK Biobank participants showing daytime light and nighttime dark exposure have independent, additive effects on depression, self-harm, and psychosis risk. He also reveals that a famous Harvard study claiming light behind the knee shifts circadian rhythm was later retracted. A sharp, data-heavy pick for listeners who want the research behind the light advice, not just the advice.
Read the full episode notesThe Secret To A Good Nights Sleep with Stephanie Romiszewski | E64
Sleep physiologist Stephanie Romiszewski argues that the anxiety around imperfect sleep, not the poor sleep itself, is what turns a bad week into chronic insomnia. She debunks the rigid eight-hour rule and the idea that lying in can meaningfully repay sleep debt, suggesting consistency across a month matters more than any single night. A necessary listen for anyone whose circadian rhythm has been hijacked by clock-watching.
Read the full episode notesSleep Doctor: If You Wake Up At 3AM, DO NOT Do This!
The Sleep Doctor explains the two separate systems governing sleep, adenosine-driven drive and clock-driven rhythm, and how your genetic chronotype (lion, bear, wolf, or dolphin) should dictate when you work, drink coffee, or have sex. He gives a specific protocol for the universal 1-3AM temperature-rebound wakeup, including 4-7-8 breathing and not checking your phone. Ideal for listeners who keep waking at the same time every night and want to know why.
Read the full episode notesThat's fifteen ways into the same 24-hour clock, from the researchers who study it to the people who help you actually fix it. Browse the full episode summaries on Episode Notes for more on sleep, light, and the biology running quietly underneath your day.