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Comment by throwkeep | Hacker News Reader

I don't understand why people are so eager to slather chemicals on their skin, when we evolved with the sun and it's not hard for most people to avoid sun burn. You just have get sun exposure on a somewhat regular basis (healthy to do anyway) and acclimate between seasons (ie, don't go abruptly from no sun to all the sun).

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Those of us in the US and Australia who are of northern European ancestry are descended from people who lived at much higher latitudes than where we live now. So no, we didn't evolve with the sun that we're currently dealing with, but a much weaker one that was lower in the sky.

We evolved to be fertile in about 15 years then die after rearing young. There is no fitness advantage to being resistant to skin cancer and living into your silver years. You will have already bred and passed on your skincancer susceptible genetic information to your offspring by the time it kills you. Evolution isn't the story of perfect, it's the story of just good enough to make progeny.

I encourage you to learn about rates of skin cancer in Australia. Most people get it. People of european genetics didnt evolve to live there

In other countries you may have a point, I am not sure

"It's not hard for most people to avoid sun burn. You just have get sun exposure on a somewhat regular basis ..."

Or, even simpler, and less controversial:

Just buy some super lightweight, long sleeved shirts ... like capilene zero or equivalent. And put on a sun hat.

Problem solved.

Yes, thanks, I should have added that too.

I live at altitude (~8000 ft) and have very fair skin. I burn within 20 minutes of being in direct sunlight. So, I’m not sure what it is I’m supposed to do.

I have very fair skin and used to burn easily, but now I don’t wear sunscreen 99% of the time I would have in the past. I just make sure to go outside regularly (starting in the winter months, here in the northern hemisphere) and expose my body to the sun, all year, and not just during vacation months.

UV intensity changes with the seasons. Expose your skin to the sun when UVs are lower and your skin will adjust to the higher UV levels slowly over time.

Before the industrial revolution, lots of work was outdoors, such as farming. Changes in industry drove folks to work more indoors, in factories and offices. Combine that with the culture of working all year and vacationing in the summertime. Folks stayed inside when UV intensity was manageable, and went outside for the bulk of their vacation, when UV levels were more intense. No wonder people think they need a product to protect their skin at all times from UVs.

I’m not against sunscreen. I’m against unnecessary use of a product that encourages more use of said product. At high altitude, I’ll sometimes put zinc on my nose and ears, though I usually wear long sleeves to protect the arms.

The idea that you simply need to tan or lay out in the sun to become resistant to skin cancer is a fallacy. That's not how your body works. There is chemical damage to your DNA taking place that your body is actively repairing, but your repair mechanism isn't perfect. There is an inherent error rate. Increase exposure to sun, you are more likely to roll the dice and have a damaged cell that evades detection by your repair mechanisms, and all cells that come from this one damaged cell will also have this mutation that makes them invisible to your defense mechanisms. these cells can slough off the mass and slip into your circulatory system and take root elsewhere in your body. Bob Marley died of skin cancer, and he was plenty tan.

Not saying fair skin people need a tan. I’m still fair skinned, even though I am outside often.

Nor am I calling for simply increasing exposure to sunlight.

All good things in moderation. There’s a balance to be found between adequate sun exposure and overexposure.

The best way is intermittent exposure. A little here and a little there. Hang out in the shade of trees in the heat of the day, out of direct light, but exposed to healthy amounts of ambient UV. Early and late hours of the day have lower UV levels as well. Just need to be more conscious about factors like that.

I used to be like that, but I started going outside for a 10 minute walk with a t shirt on every day. (I wore a wide brim hat.) Now, I never get sunburned. My skin doesn’t look any different but it stands up to sunlight a lot better. Ymmv

Wear a gardening/fishing type hat, wear long sleeve shirts that are cool breathing, and wear jeans/pants throughout the summer. I was out gardening for 7 hours straight this past Sunday in 86 degree weather with high UV index and by wearing the type of clothing to cover your skin you'll be able to stay out for hours without burning. Also you'll of course want to take measured breaks and cool downs. Look at how people have to dress in middle-Eastern countries for a reference point. Keep most the skin covered. This way, you may only need to apply any sunscreen to the tops of the hands/fingers.

I think what OP is suggesting is to go out 1 min the first day, 2 mins the second day, etc, until you have built up enough melanin in your skin and have a natural defense against it.

According to what I was taught and also the FDA websites, a tan is skin damage and increases the risk of skin cancer.

https://www.fda.gov/radiation-emitting-products/tanning/risk...

Is there any basis to this theory, at all, in science?

Bob marley died of skin cancer, and he was certainly tan.

There is a documented difference between caucasians and other races with skin cancer rates:

"[skin cancer] represents ~ 35–45% of all neoplasms in Caucasians, 4–5% in Hispanics, 2–4% in Asians, and 1–2% in Blacks."

What strikes me about this is that it's only caucasians that have elevated rates here. Many asians are light skinned but score similarly here to blacks. While it is tempting to conclude melanin offers protection and that is one theory laid out in this paper, I think there are confounding variables here that elevate the risk among caucasion populations relative to Asian populations that have about the same skin tones.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2757062/

Of course there is. It's called acclimatization to UV. Humans, plants, animals are all living beings exposed to solar radiation.

There is no fitness advantage to being resistant to UV rays. natural selection isn't about you living a long and happy life. It's about you living long enough to breed and rear offspring and whatever happens afterwards doesn't really matter, as it's not selected for. Humans are fertile in 15 years. You can get skin cancer and still make successful progeny.

I have taken to buying long-sleeved (and hooded) fishing gear to wear outdoors in the spring and summer. With modern synthetics it's not bad at all, certainly better than cotton. Same with pants.

I hope this isn't a newsflash to anyone, but you don't need to get sunburnt to get heightened skin cancer risk from sun exposure.

In New Zealand in summer the burn time gets down to below 10 minutes. Light clothing isn’t enough to protect skin.

I have burnt a child though their t-shirt. I have burnt my eyes and have burnt my skin rather too often.

Even vaguely light skin gets burnt with a short duration exposure in January or February.

I think you are under-appreciating people fierce it gets.

I mean, you ever been to a beach? You can't acclimate to being out at the beach all day.

Some people can. I am one. I will burn if I don't ramp up to it, but I eventually get very brown and can stay out all day without burning.

It’s the browning that some of us are tying to avoid - it comes with a heightened risk of skin cancers, which is very unfortunate as my unhealthy pallor could do with it.

https://www.fda.gov/radiation-emitting-products/tanning/risk...

This bad advice would raise the rate of perfectly preventable skin cancer if people followed it, which we absolutely should not.

It's because people's body fat has shifted towards polyunsaturated fats since they were told to avoid saturated fat.

Eating saturated fat and avoiding polyunsaturated fat I don't sunburn anymore. At all.

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