COVID-19 Updates – Sunlight: Optimize Health and Immunity (Light Therapy and Melatonin)

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    In our latest update, Professor Roger Seheult, MD, breaks down the latest information on how sunlight affects humans. From how the body utilizes sunlight to manage its circadian rhythm, to melatonin and cortisol production, to getting adequate infrared (IR) exposure daily.  Join Dr. Seheult for practical tips on how our relationship to light can help optimize our energy, mood, health, and immunity.


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

    The discussion begins with Dr. Seheult stressing the importance of sunlight at a cellular level. He then provides an overview on how the body generates melatonin via the pineal gland and energy via the mitochondria – and also how IR plays a key role in those processes. He also discusses the by-product of oxidative stress which left unchecked, can lead to a variety of health issues.

    He then provides an overview of the solar spectrum and the importance of IR to the body on many levels. He goes on to delve into the circadian rhythm (our internal master clock) and discusses how we “align it with reality”. This helps to maintain and regulate melatonin and cortisol production, and potentially avoid problems with sleep, weight, cancer, and diabetes that may occur with circadian dysregulation. 

    Dr. Seheult then discusses the importance of sunlight exposure as it relates to mood, depression, and seasonal affective disorder. He refers to this study on the efficacy of light therapy in the treatment of mood disorders, and this study  that supports the efficacy of midday bright light therapy for bipolar depression. He then mentions this article which covers the positive effects of artificial dawn and morning blue light on daytime cognitive performance, well-being, cortisol, and melatonin levels. 

    Dr. Seheult then gives some “dos and don’ts” for light exposure. Sun exposure and melanoma risk, and melatonin production in the body during the night AND day is also discussed. He then touches on some of the health benefits of spending time outdoors and living in green spaces such as a reduction in salivary cortisol (a stress marker). Sunlight therapies are also being used to treat various medical conditions including COVID-19, as discussed in this study.

    For more information on the topics covered in this video, please see the following links and references:


    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): 

    Sun exposure and mortality from melanoma (Multicenter): 

    Avoidance of sun exposure as a risk factor for major causes of death (JIM): 

    Interdependence… sun exposure and vitamin D to MRI measures in MS (JNNP): 

    COVID-19 and Oxidative Stress (MedCram): 

    Severe Glutathione Deficiency, Oxidative Stress and Oxidant Damage in Adults Hospitalized with COVID-19 (MDPI): 

    Vitamin D Deficiency and Outcome of COVID-19 Patients (Nutrients): 

    Ultraviolet A radiation and COVID-19 deaths in the USA (BJD): 

    Sunlight (Healthful Living): Photobiomodulation Therapy (PBMT): What is It? (Shepherd University):


    Stay Tuned for More COVID-19 Updates 

    Our COVID-19 videos are always available for free (and ad-free) at In addition, check out our full library of courses and lectures on subjects ranging from Infectious Disease to Sleep Apnea and many more!

    Meanwhile, you can find all of our COVID-19 videos compiled here.

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