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The Science of Sunlight: How 20 Minutes a Day Could Transform Your Mood, Energy, Sleep & Longevity with Dr Roger Seheult #586

Oct 14, 2025 2h 6m 16 insights
When we think of sunlight, vitamin D is usually the first thing that comes to mind. But the truth is, the full spectrum of light that we get exposed to when we spend time outside plays a vital role in how we sleep, how we feel and even how our cells create energy.   This week’s returning guest is Dr Roger Seheult, who believes that sunlight is one of the most accessible and underutilised tools we have for improving health – and the science he shares is compelling.   I’m delighted to welcome back to my Feel Better, Live More podcast for our third conversation.  Roger is a quadruple board-certified physician in Internal Medicine, Pulmonary Diseases, Critical Care and Sleep Medicine. He is also an Associate Clinical Professor at the University of California, Riverside, and Assistant Clinical Professor at Loma Linda University.   Alongside his clinical practice, he co-founded MedCram, a medical education platform with over one million YouTube subscribers, widely used by hospitals and medical schools worldwide. Roger is also a sought after lecturer and has received multiple awards for his contributions to medicine and education. His passion lies in making complex medical science accessible, and he regularly lectures to schools, hospitals and media outlets.   In this conversation, we discuss: Why deficiency in sunlight can show up as fatigue, poor sleep, inflammation or even raised cholesterol. The three “macronutrients” of light – visible, ultraviolet and infrared – and how each plays a different role in mood, immunity and cellular energy. How infrared light penetrates deep into the body, supporting mitochondrial function and how it may help protect against diseases such as diabetes and dementia. Why spending 15–20 minutes a day outside – even in the shade – can be enough to recharge our cells. The growing evidence that sunlight exposure lowers the risk of all-cause mortality, cancer and heart disease. Practical strategies for getting the benefits of sunlight safely, even if you live in colder climates or spend much of your day indoors.   Roger also shares his “eight laws of health” – simple, timeless principles that include nutrition, rest, fresh air and sunlight – and explains how neglecting them leads to the chronic conditions he often sees in his work in intensive care.   This is a fascinating conversation that will change how you think about sunlight. It isn’t just something that makes us feel good – it’s a fundamental part of how our bodies stay healthy. And the best part? It’s free and available to us all.   I hope you enjoy listening.   Support the podcast and enjoy Ad-Free episodes. Try FREE for 7 days on Apple Podcasts https://apple.co/feelbetterlivemore. For other podcast platforms go to https://fblm.supercast.com.   Thanks to our
Actionable Insights

1. Prioritize Daily Sunlight Exposure

Make a concerted effort to get outside for at least 15 to 20 minutes daily, or 20-30 minutes if the sun is low. This is considered the single biggest intervention for short-term and long-term health, impacting sleep, mood, cellular energy, and reducing all-cause mortality risk.

2. Optimize Morning Light Intake

Expose your eyes to visible light by getting outside in the morning to prevent depression and establish a good circadian rhythm, which sets the timing for all bodily processes.

3. Seek Infrared Light for Cells

Spend time outside to receive infrared light, which penetrates deeply into the entire body and restores the energy output and efficiency of mitochondria, crucial for cellular function and overall health.

4. Benefit from Outdoor Shade/Clouds

You don’t need direct sun; 15-20 minutes outside in the shade, especially surrounded by trees, provides significant infrared light. Even on cloudy days, outdoor light levels are magnitudes higher than indoors, offering health benefits.

5. Manage Nighttime Light Exposure

After 9 PM, turn off overhead lights, keep any necessary lights low in intensity and position, and avoid screens. Nighttime light can shut down melatonin production, delay circadian rhythm, and increase disease risk.

6. Follow Eight Laws of Health

Adopt a holistic approach using the ‘NEWSTART’ principles: Nutrition, Exercise, Water, Sunlight, Temperance (avoiding excess), Air (fresh air), Rest (sleep and weekly breaks), and Trust (faith/purpose). Violations of these laws are linked to chronic diseases.

7. Prioritize Winter Sunlight Exposure

Double efforts to get 15-20 minutes of sunlight daily during winter, as the peak of deaths from various diseases occurs 1-3 weeks after the shortest day of the year, highlighting sunlight’s protective role.

8. Integrate Outdoor Time into Breaks

Use lunch or other breaks to step outside, walk around, and get sunlight. This can help rejuvenate and provide energy for the afternoon.

9. Protect Skin, Maximize Infrared

If concerned about skin cancer, get infrared light benefits by sitting in the shade surrounded by trees, covering up with long sleeves and a wide-brimmed hat. Infrared penetrates clothes and reflects off foliage.

10. Avoid Sudden Intense Sun Exposure

Do not go from prolonged indoor living to sudden, intense sun exposure to avoid sunburn. Instead, aim for rational, moderate sun exposure to allow the body to adapt.

11. Embrace Green Spaces

Living in or regularly visiting green spaces with trees and plants can reduce the risk of diabetes, all-cause mortality, and cardiovascular mortality, partly due to the reflection of infrared light from trees.

12. Use SAD Light Boxes

For high latitudes or lack of morning sun, use a 10,000 lux SAD (Seasonal Affective Disorder) light box for about 20 minutes daily, placed 30 cm from your face. This provides visible light to help with seasonal affective disorder and circadian rhythm.

13. Consider Red Light Panels

If natural sunlight is impossible, especially during winter or due to work, red light panels can be beneficial for wellness. However, natural sunlight is always preferred if accessible.

14. Use Incandescent Bulbs Indoors

Use incandescent light bulbs indoors, as they produce a broad spectrum of light including beneficial infrared, unlike LED bulbs. This provides some infrared light when indoors.

15. Supplement Vitamin D if Deficient

If you are not getting enough outdoor sunlight to produce sufficient vitamin D, consider supplementing. While sunlight offers more, supplementation addresses this specific deficiency.

16. Night Shift: Optimize Eating/Sleep

If working night shifts, avoid eating at night; instead, eat after your shift, during your sleep time. Additionally, ensure your sleep environment is completely dark during daytime sleep and get bright light exposure during your ‘day’ (night shift) to align your circadian rhythm.