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There's No Such Thing as a Safe Tan (theconversation.com)
H. Peter Soyer, Professor of Dermatology, and Katie Lee, Research assistant at The University of Queensland, write: There's a lot to be said for sunshine -- both good and bad. It's our main source of vitamin D, which is essential for bone and muscle health. Populations with higher levels of sun exposure also have better blood pressure and mood levels, and fewer autoimmune diseases such as multiple sclerosis. On the other hand, excess UV exposure is estimated to contribute to 95% of melanomas and 99% of non-melanoma skin cancers. These skin cancers account for a whopping 80% of all new cancers each year in Australia.
Like any medicine, the dose counts. And in Australia, particularly in the summer, our dose of UV is so high that even short incidental exposures -- like while you hang out the washing or walk from your carpark into the shops -- adds up to huge lifetime doses. Fortunately, when it comes to tanning, the advice is clear: don't. A UV dose that's high enough to induce a tan is already much higher than the dose needed for vitamin D production. A four-year-long study of 1,113 people in Nambour, Queensland, found no difference in vitamin D levels between sunscreen users and sunscreen avoiders. Further reading: Is Sunscreen the New Margarine?
Like any medicine, the dose counts. And in Australia, particularly in the summer, our dose of UV is so high that even short incidental exposures -- like while you hang out the washing or walk from your carpark into the shops -- adds up to huge lifetime doses. Fortunately, when it comes to tanning, the advice is clear: don't. A UV dose that's high enough to induce a tan is already much higher than the dose needed for vitamin D production. A four-year-long study of 1,113 people in Nambour, Queensland, found no difference in vitamin D levels between sunscreen users and sunscreen avoiders. Further reading: Is Sunscreen the New Margarine?
What about the spray-on tan that you-know-who uses?
Table-ized A.I.
What about the spray-on tan that you-know-who uses?
Spray on "tan" isn't a tan. It's paint. Spray "tans" are tans in the same sense that soy milk is really juice. They only call it a tan because it superficially resembles one to someone who isn't looking very carefully.
From what I can tell, about 15,600 Americans die from skin cancer each year. That puts it at a little less than half your risk of dying in a car accident. So rather than turning vampire and avoiding sunlight as much as you can, just employ safe practices. Just like you buckle your seat belt when riding in a car, use sunscreen when going outdoors. Or put another way, if you're going to freak out about this and avoid going into sunlight, you should be doubly-freaked out about riding in a car.
Your analogy is accurate-- about the only thing that never seems to have evidence Fads turning like a wind-vane in a twister is coffee. Coffee is just good for you.
One thing that makes me suspect that tans are not so bad is that it's often the case that sexual attractivness is also an indicator of health or wealth or success --- that is, the general suitability of a mate for enhanced fitness.
We go to great lengths in fact to look better than we are!
And generally, on white folks, a glowing tan is considered attractive, just as a healthy flush in the cheeks is more attractive than a goth palor or a crimson palor.
So if a Tan is such a leading indicator, it might be rooted in biological fitness. That might not mean health-- it might mean your mate is an active hunter not a cave surfer--but I'd bet on health as the indication it forecasts. IN modern times, tans also are indicators of Leisure and therefore wealth, but historically that wasn't the case-- rich folks were a whiter shade of pale to specifically not be farmer-tanned.
that is, how can something that looks good be bad? Surely many ways but there's a rule of thumb here.
Some drink at the fountain of knowledge. Others just gargle.
The incidence of historical melanoma should be considered. Highly considered. As humans, historically we spent a very large amount of time working outdoors in the sunlight. Yet when we do so today, we get cancer? Wait, then what has changed? Why would evolution deselect a protective measure like this? Is it evolution or is it something else?
Diet? Pollutants? Stress? Alternative radiation exposure (radio transmissions, microwaves, CRTs)?
What is the reason, not the result, what is the cause, not the symptom. We cannot simply avoid sunlight for the rest of our lives, we need it. In the words of idiots: nerd harder, science guys!
Our fake president certainly fakes his Tan too. And he does it because he think it makes him more powerful and vigorous, so even he gets this signaling association that Tans are markers of powerful mates.
All tans are caused by damage, but not all tans are equal. There are three types of tan:
* Immediate pigment darkening: Rapid onset. Somewhat grayish appearance. Mostly gone within an hour.
* Persistent pigment darkening: Peaks within a couple hours. Mostly gone a day or so afterwards.
* Delayed tanning: Peaks after 4-7 days. Can take over a month to fully disappear.
Most tanning beds use UVA, which penetrates deeper into the skin. It causes all three forms of tanning, although the delayed tanning is not as strong as with UVB. Relative to the "therapeutic" dose, UVA tends to cause the most damage to the skin (UVB is more damaging per joule, but you use significantly less)
UVB (and UVC, although nobody uses that) also causes tanning. It's not generally used in tanning beds because it also causes sunburn (UVA, particularly UVA2, can also cause sunburn, but it's not as prone to as UVB). A particular target region however is NB-UVB (narrowband), which only has 10-20% of the sunburn risk as BB-UVB (broadband, aka, the whole UVB spectrum). UVB does not penetrate as deeply into the skin as UVA. A "therapeutic" NB-UVB dose may cause mild erythema (reddening), but no immediate darkening. This then transitions to a strong delayed tanning response. UVB tans do more to protect against further sunburn than UVA tans.
An argument can be made for switching from UVA tanning to NB-UVB tanning. But one should be clear, both damage the skin. There are medical applications for UVA or NB-UVB exposure (skin conditions like eczema, vitiligo, etc), but vitamin D is not one of them; the safest way to get it is supplements. Indeed, if you only want vitamin D, you don't want either UVA (which contributes virtually nothing) or NB-UVB exposure; you want a band in the 293-300nm region, where vitamin D synthesis is at a maximum. You can use several orders of magnitude less power than you'd use for a NB-UVB tan (and even less still vs. a UVA tan) - just a couple dozen milliwatts per square meter - and still produce daily doses of vitamin D in minutes.
Hey, guys, I'm just pleased as punch to report that it's a fleet of a hundred Vogon Battle Destroyers!
A four-year-long study of 1,113 people in Nambour, Queensland, found no difference in vitamin D levels between sunscreen users and sunscreen avoiders.
I wonder how they controlled external sources of Vitamin D. Everything from milk to cheese, breakfast cereal, orange juice, etc, as been fortified with Vitamin D. People in developed countries do not need sunlight for their Vitamin D. I don't think anyone would expect a person using sunscreen would have lower than normal vitamin D levels. If the study was not properly controlled, all it may have proven is that non-sunscreen users don't have elevated vitamin D levels.
Better known as 318230.
What if my car is a convertible!?
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It's todays Thing That Will Kill You Dead Clickbait!
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When the working class was busy toiling in the fields, a tan was considered quite unkempt among the upper echelons.
Now that the working class are stuck in cubicles, a tan is considered quite robust among the upper echelons.
Similarly, being thicker used to be more attractive, because it meant you could eat well. Walking in ridiculous shoes, and having impractically long nails is still considered attractive, because it means you don't have to do any sort of practical labor—not because working is viewed as a bad thing, but rather because most other people cannot afford to maintain those absurdities and thus it makes you stand out.
It's cool to support mass migration, because it means you get to live in a segregated, gated community that is unaffected by the growing presence of the 3rd world in your neighborhood.
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Maybe vitamin D is not the only reason the sun is good for you. https://www.outsideonline.com/...
Chris Mesterharm
"So Lindqvist decided to look at overall mortality rates, and the results were shocking. Over the 20 years of the study, sun avoiders were twice as likely to die as sun worshippers.
There are not many daily lifestyle choices that double your risk of dying. In a 2016 study published in the Journal of Internal Medicine, Lindqvist’s team put it in perspective: “Avoidance of sun exposure is a risk factor of a similar magnitude as smoking, in terms of life expectancy.”"
And also:
"Melanoma, the deadly type of skin cancer, is much rarer, accounting for only 1 to 3 percent of new skin cancers. And perplexingly, outdoor workers have half the melanoma rate of indoor workers. Tanned people have lower rates in general. “The risk factor for melanoma appears to be intermittent sunshine and sunburn, especially when you’re young,” says Weller. “But there’s evidence that long-term sun exposure associates with less melanoma.”"
So regardless of whether you believe sun is bad for your or not, I rather think saying "the advice is clear" is so abjectly wrong, you should probably take everything else that's said with a huge grain of salt. There is almost never completely clear advice when it comes to things like thins.