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How to Enhance Your Immune System | Dr. Roger Seheult

My guest is Dr. Roger Seheult, M.D., a board-certified physician in internal medicine, pulmonary diseases, critical care, and sleep medicine at Loma Linda University. We discuss the powerful benefits of light therapy, including infrared light, red light, and sunlight, for improving mitochondrial function in all the body’s organs. We also explore ways to reduce the risk of influenza, colds, and other illnesses that affect the lungs, sinuses, and gut. Topics include the flu shot, whether handwashing truly prevents illness transmission, and treatments for mold toxicity. We review the efficacy of N-acetylcysteine (NAC), the power of hydrotherapy for combating infections, and strategies for improving sleep and overall health. Additionally, we discuss air quality. This episode provides actionable, science-based tools for preventing and treating infectious illnesses. Read the full episode show notes: https://go.hubermanlab.com/3B2olpP *Thank you to our sponsors* AG1: https://drinkag1.com/huberman Joovv: https://joovv.com/huberman Eight Sleep: https://eightsleep.com/huberman LMNT: https://drinklmnt.com/huberman Function: https://functionhealth.com/huberman Our Place: https://fromourplace.com/huberman *Follow Huberman Lab* Instagram: https://go.hubermanlab.com/instagram Threads: https://go.hubermanlab.com/threads X: https://go.hubermanlab.com/x Facebook: https://go.hubermanlab.com/facebook TikTok: https://go.hubermanlab.com/tiktok LinkedIn: https://go.hubermanlab.com/linkedin Website: https://www.hubermanlab.com Newsletter: https://go.hubermanlab.com/newsletter *Dr. Roger Seheult* Med Cram: https://www.medcram.com Academic profile: https://llu.edu/academics/faculty/seheult-roger/education YouTube: https://www.youtube.com/@Medcram X: https://x.com/rogerseheult Instagram: https://www.instagram.com/medcram Threads: https://www.threads.net/@medcram Facebook: https://www.facebook.com/MedCram LinkedIn: https://www.linkedin.com/in/roger-seheult-514147b8 *Timestamps* 00:00:00 Dr. Roger Seheult 00:02:16 Avoiding Sickness, Immune System, Tool: Pillars of Health, NEWSTART 00:08:03 Sponsors: Joovv & Eight Sleep 00:10:46 Sunlight, Mitochondria, Tool: Infrared Light & Melatonin 00:19:09 Melatonin Antioxidant, Reactive Oxygen Species (ROS)/Free Radicals 00:26:38 Infrared Light, Green Spaces, Health & Mortality 00:31:35 Infrared Light, Mitochondrial Dysfunction, Disease 00:38:46 Sunlight & Cancer Risk?, Tools: UV Light, Clothing & Sunlight Exposure 00:41:01 Sponsors: AG1 & LMNT 00:43:32 Sunlight, Incidence of Influenza 00:48:41 Tools: Sunlight Exposure Duration, Winter Months 00:55:18 Infrared Lamps?, Winter Sunlight Exposure; Obesity & Metabolic Dysfunction 00:59:48 Cloudy Days; Sunlight, Primitive Therapy, Hospitals 01:11:33 Sponsor: Function 01:13:21 Artificial Lights, Hospitals & Light Therapy?, ICU Psychosis 01:22:16 Sleep & Darkness, Tools: Eye Mask, Bathroom Navigation; Meals & Light 01:28:27 Influenza, Flu Shots, Swiss Cheese Model; Flu Shot Risks? 01:38:13 Masks?, Flu; Handwashing 01:42:16 Sponsor: Our Place 01:43:57 Water, Sodium; Innate Immune System, Fever & Hydrotherapy 01:53:46 Fever, Heat Hydrotherapy, Interferon & Immune System 01:58:25 Cold Hydrotherapy, Vasoconstriction & White Blood Cells 02:09:56 N-Acetyl Cysteine (NAC), Glutathione, White Clots, Flu 02:19:28 Tool: NAC Dose & Regimen; Mucous, Flu Symptoms 02:25:25 Zinc Supplementation, Copper; Exogenous Interferon 02:28:40 Eucalyptus Oil, Inhalation 02:32:22 Air, Smoking, Vaping, Nicotine Gum 02:36:49 Fresh Air, Forest Bathing, Tool: Go Outdoors 02:40:09 Nature vs Inside Environments, Dark Days/Bright Nights Problem 02:52:38 Mitochondrial Dysfunction, Intermittent Fasting, Sunlight 03:00:43 Smell Loss Recovery 03:05:04 Mold Toxicity, Lungs, Germ vs Terrain Theory, Immunocompromised 03:11:46 Trust, Spirituality, Community, Faith; Forgiveness 03:19:46 Hospital Admission, Tool: Asking Questions 03:25:42 Zero-Cost Support, YouTube, Spotify & Apple Follow & Reviews, Sponsors, YouTube Feedback, Protocols Book, Social Media, Neural Network Newsletter #HubermanLab #Science #Health #ImmuneSystem Disclaimer & Disclosures: https://www.hubermanlab.com/disclaimer

Andrew HubermanhostDr. Roger Seheultguest
Feb 23, 20253h 28mWatch on YouTube ↗

At a glance

WHAT IT’S REALLY ABOUT

Sunlight, Heat, and NEW START: Genuine Immune Upgrades, Not Biohacks

  1. Andrew Huberman and pulmonologist/intensivist Dr. Roger Seheult detail evidence-based ways to prevent and recover from respiratory infections like colds, flu, COVID, and long COVID. They organize the discussion around the NEW START framework: Nutrition, Exercise, Water, Sunlight, Temperance, Air, Rest, and Trust, emphasizing how each pillar shapes immune and metabolic health.
  2. A major focus is on sunlight and red/infrared light: how they penetrate deep into the body, support mitochondrial function, drive local melatonin production, and correlate with lower mortality, better metabolic markers, and reduced influenza risk. They contrast this with the harms of dim days, bright nights, and blue-heavy indoor lighting.
  3. They also cover practical therapies: heat and hydrotherapy to enhance interferon and innate immunity, strategic cold exposure, NAC and zinc supplementation, eucalyptus/steam, and specific behavioral tools to speed illness recovery and support long COVID patients. Flu shots, masks, handwashing, and hospital care navigation are discussed in a nuanced, risk–benefit framework.
  4. Throughout, Dr. Seheult weaves in clinical anecdotes, historical data on phototherapy and hydrotherapy, and emerging science on forest bathing, PFAS-free environments, and the powerful role of sleep, community, and spiritual ‘trust’ in shaping both mental and physical health outcomes.

IDEAS WORTH REMEMBERING

5 ideas

Use NEW START as a practical immune-health checklist

Dr. Seheult uses NEW START (Nutrition, Exercise, Water, Sunlight, Temperance, Air, Rest, Trust) as a mental model to keep patients’ immune systems robust. Nutrition: largely unprocessed, whole foods. Exercise: mild–moderate, J-shaped curve (too little and too much both raise inflammation). Water: adequate intake plus external water via sauna, hot/cold exposure. Sunlight: daily exposure for skin and eyes. Temperance: avoiding toxins (smoking, vaping, heavy alcohol, etc.). Air: fresh, clean air plus immune-supportive forest volatiles (phytoncides). Rest: 7–8 hours of quality sleep. Trust: community and, for many, faith/spiritual grounding to lower stress and anxiety.

Sunlight and infrared light are foundational for mitochondria and immunity

Only ~38% of solar energy is visible light; ~52% is infrared, which deeply penetrates skin and tissue (up to centimeters) and scatters through the body. That infrared exposure stimulates mitochondrial efficiency and drives massive local melatonin production inside mitochondria, which quenches reactive oxygen species and supports the ‘cooling system’ of the cell. Epidemiologic data in Europe and Sweden show that higher sun exposure is associated with lower all-cause, cardiovascular, and even cancer mortality, in a dose–response fashion. Even modest daily outdoor exposure (15–20 minutes) in daylight, especially in winter, appears to benefit insulin sensitivity, triglycerides, and flu risk.

Bright days and dark nights are non-negotiable metabolic and immune levers

Modern life has created ‘dark days and bright nights’: we spend ~93% of time indoors under blue-heavy, infrared-poor LEDs, behind low-E glass that blocks IR, and then are exposed to screens and overhead lighting at night. This pattern disrupts melatonin, glucose regulation, and mitochondrial function. Practical fixes: get outside daily for at least ~15–20 minutes, even on cloudy days, ideally during lunch if mornings are impossible. Use outdoor light for circadian setting and mitochondrial support, then dim and ‘lower’ lights (lamps vs. ceiling lights) at night, avoid direct screen light, and use darkness/eye masks to protect sleep. Candlelight and fireplaces are low-lux, red/orange dominant and relatively circadian-friendly.

Heat and brief cold dramatically boost innate immunity via interferon

Raising core temperature is not just a symptom—it is a tool. In vitro and animal data show that at ~38–39°C (100.4–102.2°F), interferon production and key JAK/STAT immune signaling jump dramatically, enhancing broad antiviral defense irrespective of virus strain. Traditional hydrotherapy—20 minutes of body heating (hot bath, sauna, or hot towel ‘fomentations’ to sweating), followed by very brief cold exposure and rubbing—likely works by: upregulating interferon and transcription at higher temperature; demarginating white blood cells into circulation during vasoconstriction; and ‘locking in’ heat by peripheral vasoconstriction. These approaches were used effectively in early 20th-century influenza sanitariums and still show promise as low-cost, adjunctive treatments.

NAC can significantly blunt flu symptoms and support redox balance

N-acetylcysteine (NAC) is a glutathione precursor and mucolytic used clinically for Tylenol overdose and some lung conditions. A double-blind, placebo-controlled winter trial using 600 mg twice daily for several months did not reduce influenza infections but sharply reduced symptom severity: runny nose and sore throat markedly decreased, with an absolute risk reduction on the order of 50% (number needed to treat ≈ 2). Mechanistically, NAC supports redox balance and may disrupt disulfide bonds in von Willebrand factor polymers and mucus, potentially reducing clotting risk in viral pneumonias and thinning secretions. Many people use 600–900 mg 2x/day episodically (e.g., during illness season or early in a cold); long-term continuous high dosing lacks robust safety data, so periodic use is prudent.

WORDS WORTH SAVING

5 quotes

Maybe the lowest hanging fruit we can do right now, for literally no money, is simply to just work on getting more sun exposure in the wintertime.

Dr. Roger Seheult

We never get blue light or ultraviolet light ever without the presence of infrared light—unless it comes from an artificial source.

Dr. Roger Seheult

The engine in your house after age 40 loses about 70% of its energy output. Imagine what that would do if that were your mitochondria—and that’s basically what’s happening in the cell.

Dr. Roger Seheult

Every intervention in medicine has a benefit and every intervention has a risk, no matter what it is.

Dr. Roger Seheult

It’s not or, it’s and. Terrain and germ theory both matter. Whether you get infected depends on how good your immune system is and how virulent the burden of pathogen is.

Dr. Roger Seheult

NEW START framework for immune and overall healthSunlight, red/infrared light, and mitochondrial functionSeasonality of flu/COVID and the role of latitude and lightHeat, hydrotherapy, cold exposure, and interferon/innate immunityNAC, zinc, eucalyptus, and other illness-supportive interventionsLong COVID mechanisms and mitochondrial repair strategiesLight hygiene: indoor lighting, dim nights, and circadian healthMold, terrain vs. germ theory, and pulmonary considerationsFlu vaccines, masks, handwashing, and hospital care navigationPsychological/spiritual factors like forgiveness, community, and trust

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