Tell someone you enjoy spending time in the sun and you can almost hear the sharp intake of breath. “But what about skin cancer?” they’ll say, as if you just confessed to eating raw chicken. We’ve been conditioned to treat sunlight as a hazard, something to be feared and avoided. Slather on sunscreen, stay indoors during peak hours, cover up at all costs.
But here’s a thought worth sitting with: avoiding sunlight to prevent skin cancer is like avoiding food to prevent obesity. It’s technically possible, but the cure is far worse than the disease.
Good health, and nature in general, is all about balance.
The Sun Is Not Your Enemy
Sunlight is not some optional luxury. It is a biological necessity, woven into every system in the human body. As pulmonologist and quadruple board-certified physician Dr. Roger Seheult put it on The Diary of a CEO podcast: “A very big misconception that people have is that sunlight equals vitamin D. And therefore, if you take a vitamin D supplement, you don’t need to go in the sun. This is really something that’s now being debunked. Sunlight has far more benefits than just vitamin D.”
In another conversation on the Feel Better, Live More podcast, Dr. Seheult went even further: “If I were to say, what is the single biggest intervention that someone can do right away that would show not only benefits in the short run, but also in the long run, and is the lowest hanging fruit, there’s no question in my mind that sunlight is that intervention.”
That is a bold claim from a physician who spent years in intensive care watching patients die during the pandemic. But his conviction didn’t come from ideology; it came from observing what happened to people who lacked sunlight. During COVID, he noticed patients with higher vitamin D levels survived at dramatically higher rates. But when he gave vitamin D supplements to deficient patients, the results were underwhelming. His conclusion? Vitamin D was a marker, not the cause. It told him which patients had been getting outside and which had not. The real factor was the full spectrum of sunlight itself.
Three Nutrients in One
Sunlight isn’t a single thing. Dr. Seheult describes it as having three “macronutrients,” much like food has protein, fat, and carbohydrates.
Visible light, especially morning light, sets our circadian rhythm, the internal clock that regulates sleep, mood, gut function, and hormone production. This is why morning sun exposure has been shown to reduce symptoms of seasonal depression and improve sleep quality.
Ultraviolet B light triggers vitamin D synthesis in the skin. Vitamin D is critical for immune function, calcium metabolism, bone health, and reducing the risk of autoimmune conditions. A meta-analysis of randomized controlled trials found that people who supplement daily with 2,000 IU of vitamin D had lower rates of rheumatoid arthritis, Crohn’s disease, and ulcerative colitis.
Infrared light, the invisible component that makes up nearly half of the sun’s output, penetrates deep into the body and energizes our mitochondria, the tiny power plants inside every cell. This is the piece most people have never heard of. Infrared light can pass through clothing, bounce off trees and grass, and reach you even in the shade. Just 15 to 20 minutes of outdoor exposure can recharge cellular energy in ways that last for days.
What Happens When You Avoid the Sun
We spend roughly 93% of our time indoors. That is not a typo. In the UK, the figure is 92%. We have become, as Dr. Seheult describes it, “primarily indoor creatures who live in climate-controlled environments.”
The consequences are measurable. A landmark 20-year study out of Sweden tracked approximately 30,000 women and their sun habits. The results were striking: women who avoided the sun had roughly double the mortality rate compared to those who got the most sun exposure. The reduction in life expectancy from sun avoidance was so significant that it was comparable to smoking. Women who spent the most time outside and smoked had the same mortality rate as women who avoided the sun but did not smoke.
Let that sink in. Avoiding the sun may be as dangerous as smoking cigarettes.
This wasn’t a small or poorly designed study. It was published in the Journal of Internal Medicine in 2016 and its findings have been reinforced by subsequent research, including a UK Biobank study of over 300,000 people by dermatologist Richard Weller at the University of Edinburgh.
The Melanoma Question
Here’s where things get especially interesting. The loudest objection to sun exposure is always melanoma, the deadliest form of skin cancer. But the evidence linking regular sun exposure to melanoma is far weaker than most people assume.
Richard Weller’s UK Biobank study found that while there was a slight trend toward increased melanoma incidence with greater sun exposure, there was no corresponding rise in melanoma mortality. Meanwhile, all-cause mortality, cancer mortality, and cardiovascular mortality all went down significantly with more sun exposure.
In 2024, Weller published a paper in the British Journal of Dermatology titled “Ultraviolet radiation is not the major cause of melanoma mortality in the UK and sun exposure advice should be revised.” He argues that the widely cited claim that 86% of melanomas could be prevented through sun avoidance is based on “speculative or incorrect” data.
There is also the well-known outdoor worker paradox. You would expect people who work outside, farmers, construction workers, landscapers, to have the highest melanoma rates. But systematic reviews consistently show they do not. In fact, indoor workers who get intense, intermittent sun exposure on weekends and vacations appear to be at higher risk. A Los Angeles County study found that education level, not occupational sun exposure, was the strongest predictor of melanoma risk. Those with doctoral-level education had nearly three times higher melanoma rates than those in low-skill outdoor occupations.
As Dr. Seheult discussed on The Diary of a CEO: “He was able to show that there was no statistical increased risk of melanoma incidence, but there was a reduction in non-skin cancer mortality.” The trade-off, in other words, overwhelmingly favors getting outside.
The Balance Principle
Nature operates on balance, not extremes. Water is the most essential substance for life on Earth. Every cell in your body requires it. Without water, you die within days. And yet, drinking too much water too quickly can kill you. Water intoxication, a condition called hyponatremia, occurs when excessive water intake dilutes sodium levels in the blood, causing brain cells to swell. In severe cases, this leads to seizures, coma, and death. In 2007, a 28-year-old woman died after consuming six liters of water in three hours during a radio station contest.
Nobody would argue we should avoid water because it can, under extreme circumstances, be fatal. The same logic should apply to sunlight. The fact that prolonged, excessive, burning sun exposure carries some risk does not mean we should hide from the sun altogether. It means we should be sensible, getting regular, moderate exposure without burning, just as we drink water throughout the day without attempting to consume six liters in one sitting.
The Real Risks of Sunlight Deficiency
The science on sunlight deficiency is accumulating rapidly.
A recent US study of over 62,000 adults found that those with severe vitamin D deficiency had 2.29 times higher mortality risk and lived an average of 4.4 fewer years compared to those with sufficient levels. Approximately 1 billion people globally have a vitamin D deficiency, and about 50% of the world’s population has insufficient levels, a number that is only growing as we spend more time indoors.
A study published in the Proceedings of the National Academy of Sciences found that people with brighter daytime light exposure had up to 34% lower all-cause mortality risk. The study’s title captured the problem perfectly: “Brighter nights and darker days predict higher mortality risk.” That describes how most of us live, dim daylight hours spent inside, then bright screens all evening.
As Dr. Seheult put it: “The scurvy of the 21st century is the lack of sunlight.”
What to Actually Do
None of this is an endorsement of baking yourself on a beach for hours until you are lobster-red. Sunburn is genuinely harmful. The point is that moderate, regular sun exposure, adapted to your skin type and local conditions, is one of the most powerful free interventions available for your health.
Aim for 15 to 20 minutes of outdoor time daily, even on cloudy days. Morning light is especially valuable for setting your circadian rhythm. If you have fair skin or concerns about UV exposure, you can cover up with clothing and a hat while still absorbing infrared light. Even sitting in the shade outdoors provides significant benefits that you cannot get through a window.
If you live in a northern climate where winter sun is limited, supplement with vitamin D (and get your levels checked), but do not use supplementation as an excuse to stay indoors. The infrared and visible light components of sunlight cannot come from a pill.
The Bottom Line
We have spent decades running from the sun, and the results speak for themselves: skyrocketing rates of depression, autoimmune disease, metabolic dysfunction, vitamin D deficiency, and chronic fatigue. The message that sunlight is dangerous has, ironically, made us sicker.
Sunlight is not optional. It is as essential to human health as food, water, sleep, and air. Avoiding it doesn’t make you safer; it makes you weaker.
Get outside. Your cells are waiting.
References
- Dr. Roger Seheult on Feel Better, Live More with Dr. Rangan Chatterjee, “The Science of Sunlight: How 20 Minutes a Day Could Transform Your Mood, Energy, Sleep & Longevity” (Episode 586): https://primates.life/The-Science-of-Sunlight-How-20-Minutes-a-Day-Could-Transform-Your-Mood-Energy-Sleep-Longevity-with-Dr-Roger-Seheult-586
- Dr. Roger Seheult on The Diary of a CEO with Steven Bartlett, “Vitamin D Expert: The Fastest Way to Dementia, The Dangerous Lie You’ve Been Told About Sunlight”: https://primates.life/Vitamin-D-Expert-The-Fastest-Way-To-Dementia-The-Dangerous-Lie-Youve-Been-Told-About-Sunlight
- Lindqvist PG, et al. “Avoidance of sun exposure as a risk factor for major causes of death.” Journal of Internal Medicine, 2016: https://onlinelibrary.wiley.com/doi/full/10.1111/joim.12496
- Weller RB, Gu J. “Ultraviolet radiation is not the major cause of melanoma mortality in the UK and sun exposure advice should be revised.” British Journal of Dermatology, 2024: https://pubmed.ncbi.nlm.nih.gov/39474912/
- “Higher ultraviolet light exposure is associated with lower mortality: An analysis of data from the UK Biobank cohort study.” Health & Place, 2024: https://www.sciencedirect.com/science/article/pii/S1353829224001564
- “Strange but True: Drinking Too Much Water Can Kill.” Scientific American: https://www.scientificamerican.com/article/strange-but-true-drinking-too-much-water-can-kill/
- “Vitamin D, premature mortality, and life expectancy among US adults.” Archives of Public Health, 2025: https://link.springer.com/article/10.1186/s13690-025-01785-z
- “Brighter nights and darker days predict higher mortality risk.” Proceedings of the National Academy of Sciences, 2024: https://www.pnas.org/doi/10.1073/pnas.2405924121
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