Wednesday, February 8, 2023
Mitochondrial Health

Sunlight: Optimize Health and Immunity (Light Therapy and Melatonin)

Sunlight provides so much more than just Vitamin D: learn from Dr. Seheult of about the myriad of benefits from optimizing our exposure to light.

Roger Seheult, MD is the co-founder and lead professor at
He is Board Certified in Internal Medicine, Pulmonary Disease, Critical Care, and Sleep Medicine and an Associate Professor at the University of California, Riverside School of Medicine.

This video was recorded on January 21, 2022

0:00 Intro
6:50 The solar spectrum
13:00 Circadian rhythm highlights and chart
15:15 What is regulated by circadian rhythm
16:30 Circadian dysregulation
22:30 Circadian master clock
26:41 Blue blockers
29:15 Light & mood regulation & seasonal affective disorder
31:14 Dawn simulation light and light therapy box demo
35:45 Light & cortisol
38:15 Melatonin from the pineal gland
42:00 Morning dos and don’ts
44:00 Evening dos and don’ts
48:30 Mitochondria & melatonin
49:45 Melatonin night AND day
51:00 Details of melatonin production
59:00 Melatonin summary
1:02:30 Infrared radiation
1:20:45 Sun exposure & melanoma risk
1:26:00 Sunlight penetrates bone & brain
1:29:00 Sun exposure and Covid-19
1:40:00 Infrared inhibited by glass
1:43:00 Infrared summary
1:53:00 Summary & tips


The Relationship Between Lux, Lumen and Watt (Tachyon) |

Infrared and skin: Friend or foe (Science) |

Melatonin as a potential anticarcinogen for non-small-cell lung cancer (Oncotarget) |

The efficacy of light therapy in the treatment of mood disorders (AJP) |

Adj. Bright Light Therapy for Bipolar Depression (AJP) |

Effects of artificial dawn on subjective ratings of sleep inertia and dim light melatonin onset (Chronobiology Int) |

Effects of Artificial Dawn and Morning Blue Light… (Chronobiology Int) |

Circadian rhythms in the hypothalamo-pituitary-adrenal (HPA) axis (MCE) |

Reduced cancer incidence among the blind (Epidem) |

Evening use of light-emitting eReaders negatively affects sleep (PNAS) |

Ocular input for human melatonin regulation (NEL) |

Melatonin and the Optics of the Human Body (Melatonin) |

Melatonin in Mitochondria (APS) |

Opportunities.. of Fluorescent Carbon Dots (CPD) |

The health benefits of the great outdoors (Environ) |

Interplay between up-regulation of cytochrome-c-oxidase (Nature) |

Red/Near Infrared Light Stimulates Release of an Endothelium Dependent Vasodilator (FRBM) |

Effect of daylighting on student health (CMSE) |

Shining the Light on Sunshine (Clinical Endo) |

Associations of Outdoor Temperature (JCEM) |

Relationship between sun exposure and melanoma risk (EJC) |

We cannot post all links and references here (due to video description length limitations) but will post them at the MedCram Blog:

All Dr. Seheult’s videos are at (including more discussion on red light therapy, infrared light benefits, what is melatonin, etc.)

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Media Contact: [email protected]
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Video Produced by Kyle Allred
Thanks to Amanda Taylor, PA-C



MedCram medical videos are for medical education and exam preparation, and NOT intended to replace recommendations from your doctor.

#COVID19 #Omicron #Coronavirus


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43 thoughts on “Sunlight: Optimize Health and Immunity (Light Therapy and Melatonin)
  1. Has anyone ever studied the homeless population and occurrence of diseases that result from lack on sunlight? Haven't finished listening…so I apologize if you answered this.

  2. Dear Dr. Seheult i have a question: if you work in night shifts (for example if you work in a hospital), when is the best time to take a melatonin supplement in order to: a) reap the maximum health benefits from melatonin and b) to adjust your disrupted waking-sleep cycle???? when you go to sleep after the night shift (that is in the morning) or before you begin the night shift (in the late evening for example)???? this is a very crucial piece of information that it is not elucitated.

  3. Dr. Seheult if a person had a fire down close to the ground, recorded with a digital camera and displayed on a flat panel digital tv with films in place to block the blue 460-484nm spectrum, sitting on the floor vertically against a wall of course , would that be a beneficial light source for after 6pm in winter months in northern united states?
    im thinking of setting up an underground bunker to be able to simulate above ground via digital windows etc…

  4. Napping is another big question. In our own circles many friends went to a nap schedule with COVID. It would be interesting to know if there's any effective science about napping and health.

  5. This is all so very interesting and I have sent it to my son he has been working graveyard shift which you know starts at 11:00 p.m. and ends at 7:00 a.m. he has been doing this for approximately 3 years wondering if any of these light therapies or are there any supplements that he should be taking, when is the best time to take a vitamin d supplement, should he take melatonin at all in the morning or starting at 5:00 a.m. so he can come home and sleep or should he stay awake after his shift until a certain time what is your best advice for someone who works these hours thank you very much this was one of the best videos and informative pieces I have seen and I thank you again.

  6. What an amazing podcast! Thank you for giving us such important informations. I love the fact that Kyle was there with you on the presentation and asking such important questions so that you can reinforce the valuable details and facts that we needed to know and pass on to our family and friends. I shared that the videos with my family members. Thank you Dr. And Kyle for taking the time to share such valuable informations to all of us.

  7. When the research on near infrared (NIR) saunas and lights comes out, it would be helpful to present it for us and, again, to make some practical recommendations. For example, for a work-at-home schedule, would outside exercise before nine a.m. followed by NIR sauna or NIR light exposure indoors provide at least the basic exposure needed? Perhaps with additional NIR exposure at the end of the workday, either with a walk or some sort of indoor device. On top of following the night-time guidelines given here, of course.

  8. Melatonin, stops Nephrotic Syndrome, easy peasy in my kod who was vax injured 2 years ago at age 6. 1 year standard prednisone hell.
    1.5 years using 5,20,50,100,150 mg , whatever I need as soon as NS eye edema is obvious. Divided doses. starting morning, lunch, dinner and bedtime . In a single 24 hour cycle, she returns to normal and life goes on.

  9. I'm concerned about in home lighting. I know bright white fluorescents or staring at a laptop are not good, but what about LED lights-everyone is going to LED in everything. They come in different brightness & the colors they omit. How do you pick an overhead fixture in your kitchen which is one of the most used parts of the house. You did speak to this, but I guess we still don't have an LED light that covers the red spectrum. Please let us know what indoor lights we should use NOW. Thank you for the info. Very enlightening.

  10. In regards to near-infrared what happens in the winter when were all bundled up does near-infrared penetrate that if not does that mean we go through the winter without mitochondria having melatonin

  11. Ok sunlight is the best at certain times as mentioined however for those who cannot for some reason Please use IR LED lights and panels etc to get the IR light to your mitochondria at other times. RED Light therapy is well studied and produces the same results. Also different wave lengths ie; 450-1050 nm can be ued in LEDs to help different health conditions. Red, Green, Yellow, Blue etc Search You Tube for much info on these and what health results have been validated. I use Red light panels and torches and photo puncture points to get results. See photobiomodulation on you tube. Thanks

  12. I used to work one of the more rough night shifts, midnight to 8 AM. I would always be just dying at around 6 AM. but when I would leave the factory at 8AM I would get all this sunlight on the way home and it was like getting a second wind. It was always worst when I watched the sun rise. I never knew why or if this was just me.

  13. Another thing you are exposed to when going out into the sun … is different air than inside. This could also be having an effect. Also it is likely that people going outside more are doing more physical activity.

  14. Wow! Just love this video! So informative. My son is a submariner and sometime he spends up to five months away at sea without ever coming up to the surface. Their diets on board are pretty poor as well. I worry about his and his colleagues health.

  15. ? What are the upper LIMITS of unprotected eye exposure for the macula and for skin cancer risk for seniors of different darkness of skin, at different latitudes? I. discovered my Irish/English father's melanoma (thanks to my dermatologist's office brochures)and although we learned to wear sun block at about 30, earlier, we used baby oil and iodine! I am delighted to learn that being out of direct sun in the green world of Nature is most of or all we need for our NIR infrared needs! This would be easier on our eyes, no?

    Most of my MD colleagues and friends urge me to wear sunglasses ALL the time I am outside before dark. ( I mention seniors not only because I am 72, but because many fail to include our issues and necessary modifications of advice for our bodies.) As seniors, even apparently very healthy ones, are we, is our skin, are our eyes more vulnerable to damage by over exposure?

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