What We Really Know About Sun Exposure

A foreword from Patty

Since I turn 50 this year I decided it’s probably time to start regular “mole patrol” appointments for identification and removal of any areas suspicious for skin cancer. I’d been hearing about Dr. Zirwas through shared patients over the last few months, and could tell that he seems to do a lot of “out of the box” thinking for chronic skin conditions – and just as important– that patients really like him.

During my visit, Dr. Zirwas discussed his views on sun exposure –  he is the only derm I’ve ever met who didn’t lecture me about my love of sunbathing. I’ve done a lot of my own research, and my long time views lined up with what Dr. Zirwas had to say – so it was nice to have validation and the peace of mind only a derm can give you.

I asked him right there on the spot if he would mind writing a guest blog for me so I could share this info with my patients.  He readily agreed, but asked that he be allowed to provide references to (hopefully) cut down on the blow-back he expects from other area derms.  So we’ve included those in his article below. First an introduction…

About Dr. Zirwas
Dr. Matthew Zirwas

Dr. Zirwas received his undergraduate and medical school degrees from the University of Pittsburgh. He completed his dermatology residency at the University of Pittsburgh as well, developing an interest in contact dermatitis, which led to additional training at Penn State University and the Cleveland Clinic.

One of the most important moments of Dr. Zirwas’ life happened while he was a young dermatologist and realized that so much of what he was being taught to tell patients didn’t have any proof to back it up. Even worse was that much of what he was supposed to tell them either didn’t work or was making their problems worse. At that moment he started looking for the actual causes for what he was seeing in his patients and for explanations that made sense, and he hasn’t stopped since.

Over the ensuing 15 years, he has developed innovative, effective treatment approaches that have helped hundreds, even thousands of patients. His approaches to treating these patients have garnered significant recognition in the dermatology world, with Dr. Zirwas publishing over 120 peer-reviewed medical articles and giving hundreds of lectures all over the country. Not all of the attention has been good, though, as much of what Dr. Zirwas says doesn’t fit with what the “conventional wisdom” is in dermatology.

The most frustrating things for him are that there are still so many things that we don’t have good explanations for, or, that we do have a good explanation for, but not a good way to fix. He is constantly listening to his patients and reading the medical journals, looking for clues to send him in new directions.

sun scribbleWhat We Really Know About the Sun

Matthew J. Zirwas, MD, Board Certified Dermatologist and author of  more than 100 peer-reviewed journal articles.

If you’ve ever asked your dermatologist what you should know about sun exposure, the answer has probably sounded something like this:

  • Sunlight contains ultraviolet radiation (UVR).
  • Ultraviolet radiation causes skin cancer and aging of the skin.
  • Therefore, people should avoid exposure to sunlight.

It’s simple, bite size, repeatable, easy… and totally wrong.

Well, maybe not TOTALLY wrong, but at a minimum, incomplete and misleading.  How do we change it to make it more accurate?  Let’s try adding a few more facts.  Every statement below is true.

A Few More Facts

  • Sunlight contains ultraviolet radiation.
  • Ultraviolet radiation is the main cause of certain types of skin cancer, specifically basal cell and squamous cell carcinoma.
  • Basal cell and squamous cell carcinoma are almost always easy to treat and very rarely kill anyone.
  • Ultraviolet radiation, especially sunburns, slightly increases the risk of getting melanoma, but it DOES NOT increase the risk of dying from melanoma. [1]
  • Compared to kids who go to schools with regular light fixtures, kids in schools that have low level ultraviolet radiation being released by the light fixtures are taller, have fewer cavities, miss fewer days of school, and do better academically.[2]
  • Your body produces endorphins when your skin is exposed to ultraviolet radiation and endorphins put you in a better mood.[6, 7] Being in a better mood benefits your cardiovascular, immune, and nervous systems.
  • Ultraviolet light reduced the risk of obesity in mice via a mechanism that is totally independent of vitamin D.[5]
  • Ultraviolet radiation reduces blood pressure and this very likely leads to a decreased risk of heart attacks, strokes, and other cardiovascular problems. This has nothing to do with vitamin D – it is because ultraviolet radiation increases nitric oxide levels.[3, 4]
  • People who get more sun exposure are less likely to get depression, rheumatoid arthritis[8-10], multiple sclerosis[9-11], and diabetes.[9, 10, 12, 13]
  • People who get more sun exposure have less risk of getting breast cancer[14, 15], lung cancer[16], and prostate cancer[17].
  • In studies in which people are given vitamin D supplements, the vitamin D doesn’t seem to reduce cancer risk.[18]
  • Women in Sweden who get the most ultraviolet exposure are the least likely to die.
  • All of the studies that show an association between sun exposure and decreased risk of health problems could be coincidences since sun exposure only happens outdoors. It could be that spending time outdoors while wearing sunscreen and sun protective clothing is just as good, or even better, than being outdoors without sunscreen.
  • The number of people who die from the diseases that sun exposure may benefit is so much bigger than the number who die from skin cancer that if avoiding sun eliminated 100% of skin cancer deaths but increased the number of deaths related to the other diseases by 0.1%, avoiding the sun would still increase your risk of dying.

My Conclusions Based on These Facts

This is a lot more complicated than what you usually hear from dermatologists. And it doesn’t necessarily lead to an easy recommendation. When I think about all the evidence and data I’ve read, here is what I think:

  • Sun exposure definitely increases your risk of basal cell carcinoma, cutaneous squamous cell carcinoma, and some types of melanoma. It doesn’t increase your risk of dying from melanoma. It does increase your risk of dying from cutaneous squamous cell carcinoma (cSCC), but cSCC is much less dangerous than melanoma and dying from it is easy to prevent by getting checked by a dermatologist regularly.
  • Sun exposure probably decreases your risk of numerous other health problems via skin production of vitamin D, nitric oxide, endorphins and other, as yet undiscovered, substances. We don’t know exactly how much it decreases them.
  • Taking vitamin D supplements doesn’t have ALL the same benefits as getting sun exposure.
  • We don’t know for sure which of the above is more important – in other words, we don’t know if the benefits of sun exposure overall outweigh the increased risk of skin cancer.
  • However, based on the number of people affected and the seriousness of the diseases that sun exposure probably affects positively vs the number of people affected and the seriousness of skin cancer, it is likely that sun exposure is an overall benefit to health. This is supported by the best study looking at the relationship between ultraviolet exposure and risk of death.

What I Do For Myself & My Family

  • I get as much unprotected sun exposure as I can (without getting a burn).
  • Sunburns are bad and I try to avoid them.
  • It makes sense to wear sunscreen on your face and neck, as this will prevent skin aging in these areas and these are the highest risk areas for skin cancer, so you get the most benefit in skin cancer reduction by protecting these areas.
  • If you’re over 50 and have gotten a lot of sun or if you have a lot of bumps on your skin, get checked by a dermatologist.


  1. Berwick, M., C. Pestak, and N. Thomas, Solar ultraviolet exposure and mortality from skin tumors. Adv Exp Med Biol, 2014. 810: p. 342-58.
  2. Hathaway, W., A Study Into the Effects of Types of Light on Children – A Case of Daylight Robbery, in IRC Internal Report No. 659. 1994, Institure for Research on Construction: Ottawa, Canada. p. 11-29.
  3. Liu, D., et al., UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure independently of nitric oxide synthase. J Invest Dermatol, 2014. 134(7): p. 1839-46.
  4. Oplander, C., et al., Whole body UVA irradiation lowers systemic blood pressure by release of nitric oxide from intracutaneous photolabile nitric oxide derivates. Circ Res, 2009. 105(10): p. 1031-40.
  5. Geldenhuys, S., et al., Ultraviolet radiation suppresses obesity and symptoms of metabolic syndrome independently of vitamin D in mice fed a high-fat diet. Diabetes, 2014. 63(11): p. 3759-69.
  6. Jussila, A., et al., Narrow-band ultraviolet B radiation induces the expression of beta-endorphin in human skin in vivo. J Photochem Photobiol B, 2016. 155: p. 104-8.
  7. Levins, P.C., et al., Plasma beta-endorphin and beta-lipoprotein response to ultraviolet radiation. Lancet, 1983. 2(8342): p. 166.
  8. Arkema, E.V., et al., Exposure to ultraviolet-B and risk of developing rheumatoid arthritis among women in the Nurses' Health Study. Ann Rheum Dis, 2013. 72(4): p. 506-11.
  9. Ponsonby, A.L., A. McMichael, and I. van der Mei, Ultraviolet radiation and autoimmune disease: insights from epidemiological research. Toxicology, 2002. 181-182: p. 71-8.
  10. Artukovic, M., et al., Influence of UV radiation on immunological system and occurrence of autoimmune diseases. Coll Antropol, 2010. 34 Suppl 2: p. 175-8.
  11. van der Mei, I.A., et al., Regional variation in multiple sclerosis prevalence in Australia and its association with ambient ultraviolet radiation. Neuroepidemiology, 2001. 20(3): p. 168-74.
  12. Staples, J.A., et al., Ecologic analysis of some immune-related disorders, including type 1 diabetes, in Australia: latitude, regional ultraviolet radiation, and disease prevalence. Environ Health Perspect, 2003. 111(4): p. 518-23.
  13. Mohr, S.B., et al., The association between ultraviolet B irradiance, vitamin D status and incidence rates of type 1 diabetes in 51 regions worldwide. Diabetologia, 2008. 51(8): p. 1391-8.
  14. Anderson, L.N., et al., Ultraviolet sunlight exposure during adolescence and adulthood and breast cancer risk: a population-based case-control study among Ontario women. Am J Epidemiol, 2011. 174(3): p. 293-304.
  15. Mohr, S.B., et al., Relationship between low ultraviolet B irradiance and higher breast cancer risk in 107 countries. Breast J, 2008. 14(3): p. 255-60.
  16. Mohr, S.B., et al., Could ultraviolet B irradiance and vitamin D be associated with lower incidence rates of lung cancer? J Epidemiol Community Health, 2008. 62(1): p. 69-74.
  17. Colli, J.L. and W.B. Grant, Solar ultraviolet B radiation compared with prostate cancer incidence and mortality rates in United States. Urology, 2008. 71(3): p. 531-5.
  18. Bjelakovic, G., et al., Vitamin D supplementation for prevention of cancer in adults. Cochrane Database Syst Rev, 2014(6): p. CD007469.

2 thoughts on “What We Really Know About Sun Exposure

  1. Amy Weinhold says:

    That is great to finally hear from a professional what I always thought to be more accurate about the sun and your skin. I’m so tired of hearing about “stay out of the sun 100%”. If the sun were really that dangerous, we would all have cancer, but we’ve survived in the sun now for thousands of years without suntan lotion. All you have to do is treat your exposure with just a little common sense! Your body speaks to you – listen to it! You’ll know when it’s time to go for some cover. Excellent article.

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