Meet Mark

Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

Tell Me More
Stay Connected
November 27, 2006

Sunscreen May Not Be Your Friend

By Mark Sisson

Let me be the first to say: I am pro-sunlight. I’m not talking about weather patterns, either. I’m talking about exposing yourself to some rays. I spend a fair amount of time outside soaking up the sun’s energy (of course, being careful not to burn). Although evidently most dermatologists believe we would be better off spelunking in caves 24/7 and covering ourselves in head-to-toe black garb whenever we venture out, my own evolutionary perspective leads me to believe we were designed to get sunlight almost every day and that our health suffers if we don’t get enough.

In fact, recent studies show that, as a result of our shunning the sun, many of us suffer from Vitamin D deficiency and a resulting loss of bone density and immune function (to name just a few effects). Some researchers opine that more people die from lack of sun than from too much sun! But, I digress.

I came across an article the other day that piqued my curiosity since it dealt with the combination of running and sunning. It basically showed that marathoners (e.g. formerly yours truly) tend to get skin cancer at higher rates than other people. The more they run, the higher the incidence of skin cancer.

My take on what’s happening is that not only are runners exposed to more sun (which can cause DNA damage in skin cells – ergo, cancer), but they are also bathed in more free-radicals overall from the excessive oxidation of glucose and fats.

We know that sun exposure does deplete the skin of the antioxidant Vitamin C. Stick with me on this: the act of running tends to divert blood flow away from the skin, starving it of additional important antioxidants that could neutralize the free-radical damage in the skin tissues. Add to that the enormous amounts of stressful cortisol marathoners pump out doing this unnaturally high steady-state oxidative work and we not only get the DNA damage, we get the immune-bashing effects of the high-stress activity. The effect: more DNA damage and a reduced ability to recognize that damage and take steps to eliminate those cells and/or repair the damage.

That’s one reason (among many) that I have doused myself with antioxidants inside and out for over 20 years now. That’s also why one of my mantras is: a little running is OK – a lot is bad.

The above article also brings up other points of discussion, such as whether the reliance on inferior sunscreens might be another cause. This is vitally important to discuss and it’s not getting much attention in the mainstream media. It appears that for the past 30 years so-called sunscreens have been good at blocking UVB rays (the ones that burn) but not UVA (the ones primarily responsible for DNA damage and skin cancer). Thank you, FDA. The terrible effect is a generation of gung-ho health fanatics slathering on sunscreen and running 40, 50 or 100 miles a week. The fact that we didn’t burn only lead us to believe we could stay out even longer. Little did we know that the burning of skin might have been a great first warning to get the hell out of the sun! How’s that for nature’s way of saying “Yo! Enough!”? Unfortunately, the sunscreen gave us the false notion we were invulnerable. Oops. Guess big Pharma was wrong again. More on that later….

[tags] sunscreen, vitamin D, free radicals, marathon, antioxidants, DNA damage, skin cancer, UVA, UVB, cortisol, sun block, SPF, immunity, bone density, osteoporosis, dermatology [/tags]

Subscribe to the Newsletter

If you'd like to add an avatar to all of your comments click here!

Leave a Reply

15 Comments on "Sunscreen May Not Be Your Friend"


Sort by:   newest | oldest
7 years 10 months ago
I don’t remember where, but I seem to recall reading that a diet high in antioxidants protects against sunburn, and if you get enough antioxidants you don’t need sunscreen. I’m not sure how much is “enough” or what level of sun exposure is available. But the point is: Grok didn’t have sunscreen, yet he seems to have survived all right. The Sun has been around for the entirety of our evolution, so it makes sense that the body can handle it. Given the right kind of sustenance, of course. Anybody out there have any testimonials? Does anyone know from experience… Read more »
Del Mar Mel
Del Mar Mel
7 years 9 months ago
I have also read the same. I had an interesting experience one day that made me a believer. I commute back and forth between Del Mar and Santa Barbara (SoCal). Normally it’s a 3 hr drive and though I have a convertible I’ve learned to only put the top down for 1/2 of the drive because I seem to get bizarre tan lines/ sunburned on either the tops of my ears or a line where the seat belt runs across my chest. On one particular gorgeous day I put the top down and hit a ton of traffic in Malibu.… Read more »
6 years 4 months ago

This is a very interesting subject… I am a fair-skinned redhead and have always had to limit my sun exposure. I’vebeen eating primally for the last few months, including tons of antioxidants. Today I didn’t really think about sunscreen (besides my usual spf face lotion) before I went out for a few hours at the park… It was really hot and sunny and i swore my arms and legs must be getting fried. Much later now and no burn, just a few more freckles!

Art of Lifting
6 years 2 months ago

I remember once reading that sunscreen has chemicals in it that can give you cancer. I personally don’t know anything about that, but I do know that it pays to be careful anyway.

I like the approach you posed in the article, that burnt skin is a sign that you’ve spent too long in the sun, not that you should’ve applied more sunscreen.

5 years 7 months ago

I think the best way is to expoze in sun in right hours of the day, morning and afternoon, and to avoid use of suncreams. What the reason to burn under the sun as a steak?

5 years 6 months ago

I am a bit concerned about sun exposure. I am Indian, and have brown skin, and have been told to avoid sun exposure, mainly because it will make my skin look darker. Other than that, I have heard many ills against sun exposure, and recently ran into this article:

Can Mark or anyone shed some light on this? I am getting contradictory message. ALso, how much does kin color dictate sun exposure?-that is really biggest question.

I'm not Mark but I wanted to reply Haha
I'm not Mark but I wanted to reply Haha
2 years 5 months ago
What I know about skin colour and the amount of sun exposure you need, is that people with dark skin tend to need a bit more sun than people with light skin. This is become the sun easily gets through light skin and gives them their vitamin D. If you live in a country much nearer the equator, then everday-casual exposure is no problem for you. If you live in colder countries on the other hand, it may be difficult for you to get enough sun (if it’s not summer), since 1) you limit going out because it’s cold and… Read more »
5 years 5 months ago
I know this is an old post, but I’d like to add my 2 cents. I’m an esthetician, so you’d think I’d be all about sunscreen. I am very against it. What we learned at school was that the very chemical reaction that makes sunscreen prevent burning CAUSES FREE RADICALS. So not only do you have a false sense of security (I put on my SPF 50, I can be out all day!), but you’ve just put something that creates free radicals on your skin. Free radicals are a known contributing factor to cancer. The rate of skin cancers have… Read more »
5 years 2 months ago

I believe the reason so many distance runners get cancer is that they consume buckets of sugar before, during, and after running, and all day long for that matter. Cancer loves sugar.

Christine Mudge
Christine Mudge
4 years 10 months ago
Let’s not dismiss the role of skin color from this equation. The reason Grok was black (from our human origins in Africa) was to protect against the harmful effects of sunlight. As homo sapiens spread out, and inevitably several groups made it into the northern reaches of the globe, there was less sunlight available for much of the year thus the skin lightened to absorb more vitamin D. Studies suggest that this was evolutionary advantageous because those women who were deficient had malformed bones and pelvises, thus unable to reproduce. Now, for those of us who are white, it stands… Read more »
3 years 4 months ago

I followed this advice for 1.5 years after being very sun aware and a sunscreen addict. 1.5 years later and now



and one of them is Melanoma. So now I get to wonder if one day I’ll die from an almost entirely preventable cancer.

This article’s advice is DEADLY

2 years 11 months ago
A: Exercise does NOT divert blood flow away from the skin. Quite the contrary, actually. Regulation of body temperature takes precedent, and cutaneous blood flow INCREASES to rid the body of heat. It’s why your veins appear so dilated when you exercise. Ergo, your hypothesis is misguided. B: UVA/UVB/UVC differentiation is based upon arbitrary cutoffs. Skin cancer (basal and squamous cell) is most often caused by UVB, with minimal “UVA” contribution. Melanoma is a grey zone, that appears multifactorial, related to genetics and UVA/UVB exposure. C: Based on your evolutionary observations, I’d have expected you to note the stark differences… Read more »
1 year 8 months ago
Interesting comment Blake. I am more leaning towards the fact you mentioned above only relatively recently peoples have evolved in varying sun light and UV regions. Much the same philosophy the we are eating based on a pre-agricultural diet, a blanket rule does not fit. I live in Australia and only a few generations ago my family was from England. Suddenly putting people who evolved with English sunshine into the harsh environment of Australia without thousands of years to evolve seems more obvious than antioxidants. The natives of Australia are very dark as they are adapted. Although I think a… Read more »
9 months 24 days ago

Cant believe a college course i am taking refers to your page, Mark.
Not in a good way either.
Oh well, keep up the good work.

1 month 20 days ago

Same here. Kind of sad. I believe in some of the things that you state but they are looking at you as not a credible source.