MaintenanceMode 6 days ago

Well, this is oddly personal for hackernews but what the heck. This is pretty interesting to me. I’ve been living outdoors for the last 12 months, and I’ve noticed some significant changes in libido. It’s been on my mind quite a bit (not only for the obvious reasons but also wondering why this is happening to me). There’s a lot of factors of course, going from a mostly sedentary indoor life to a mostly actively outdoor life but this is fascinating. My SO is much more careful than I am with UV exposure and hasn’t seen the same change but again, too many factors to control for in this sort of anecdotal experience.

  • hh3k0 6 days ago

    Interesting nonetheless, thanks for sharing!

    Slightly related: I've decided to stop using suncreen altogether for day-to-day sun exposure. My mood and overall sense of happiness increased significantly – in fact, it seemed to have helped more than my antidepressants ever did. (My libido did not increase but my antidepressants are pretty much libido killers.)

    • kiliantics 6 days ago

      I don't put on sunscreen unless I know I will be outside unexposed for over an hour while the UV index is 5+. If I can wear a hat and long sleeves or know there will be shady spots, I still avoid sunscreen. I rarely get anything close to a burn and I believe this is probably healthier than the religious screen use that everyone seems to recommend.

    • axpy906 6 days ago

      Got to watch out with sunscreen too. Many brands have ingredients that can pass the blood brain barrier.

      • sizzle 6 days ago

        Shit like what??

        • orangepurple 6 days ago

          Zinc oxide and titanium dioxide are the only two sunscreen ingredients the FDA considers truly safe sunscreen ingredients, and as someone with a basic understanding of biology, I tend to agree with them on this (1). Zinc oxide and titanium dioxide nanoparticles refuse to penetrate the skin even when rubbed into open wounds and they have negligible effects in vivo when used topically. Additionally and crucially they block UVA, the major skin cancer promoter, which won't give you sunburns. Zinc oxide is the most effective broad spectrum sunscreen. Titanium dioxide is less effective with UVA absorption. All other sunscreen compounds function after being absorbed into the skin. Unfortunately they also get into the bloodstream where they act as hormones such as estrogen mimickers (unintentionally).

          The only downside of zinc oxide and titanium dioxide is that they are awful to apply (you need a good technique) and you will probably look awful after application. It may be better to apply less material at a time but more often. Most manufacturers recommend every 80 minutes. I think this is defined by FDA regulation.

          Since zinc oxide and titanium dioxide are semiconductors, they can both reflect and absorb UV. I think there is a large gap in understanding by sunscreen manufacturers of how these nanoparticles perform on a quantum level. I hold out hope that some chemist can further engineer these nanoparticles perhaps through an innovative coating to further improve performance and appearance when applied. I think there is still a lot of money being left on the table and these compounds are under appreciated, not understood well, nor developed enough to this day. Fortunately the sunscreens containing them do work today.

          [1] https://www.fda.gov/media/153964/download

          • water8 5 days ago

            Of all the metalic elements, Zinc is relatively harmless and actually has been shown to inhibit the process of viral replication.

            By the way no one knows how elements behave on the quantum level we don’t have a quantum computer nearly powerful to simulate anything more than hydrogen

            • orangepurple 4 days ago

              There are some relevant effects of UV on these semiconductor sunscreens to consider. For example:

              It is generally agreed that UV absorption excites an electron from the valence band to the conduction band of the semiconductor. The resulting excited electrons, in the otherwise empty conduction band, and the “positive holes” in the valence band allow charge transfer to the TiO2 surface which facilitates oxidation of surrounding molecules. Sometimes direct charge-transfer causes the oxidation.

              https://www.mdpi.com/1420-3049/19/11/18192/htm

              Some questions which stem from this finding include: what is being oxidized on the skin in its immediate vicinity when UV makes contact with the semiconductor sunscreen? What are the implications?

              Is there any performance difference between nanoparticle sizes?

          • vostok 6 days ago

            I mostly use zinc oxide sunscreen and don't think I look awful, which I understand is both a personal opinion and also something that can vary from person to person based on skin tone.

            • no-dr-onboard 4 days ago

              I think they’re referring to the white overtone that zinc based sunscreen leaves due to poor absorption

              • hh3k0 4 days ago

                That's what I thought, too.

                I mean, just google "Zuckerberg sunscreen".

      • icoder 6 days ago

        So has water

    • milesvp 6 days ago

      I’ve been seeing more and more evidence that we may not be getting enough UV exposure in general in the US. Vitamin D production is big, but what fewer people know about is nitric oxide which is also sythesized from UV exposure. It is a muscle relaxer that lowers blood pressure. It would undoubtedly have a positive effect on your mood.

      • dbsights 6 days ago

        .. and your dick. Raising NO is the mechanism of action for Viagra.

  • winternett 6 days ago

    I try to keep full spectrum light bulbs in as many rooms as possible within in my house, which also helps a bit, along with going outdoors as much as possible and supplementing vitamin D.

    There is a whole lot of new conflict world wide out of the isolation and conservation that recent pandemics have caused. It's been a really frustrating missed opportunity by social and dating apps that they don't better help people to navigate social communication, scientifically based health advice, and relationship building/improvement with all the human isolation that is occurring and growing fast.

    The term gonads though has always triggered Beavis and Butthead giggles for me ever since high school.

  • LorenPechtel 6 days ago

    I haven't noticed any changes since I got back into hiking but I'm careful with the sunscreen--I live in the desert where the sun is brutal, any mistake is liable to result in a burn.

    I have been seeing many hints recently that UV might be good for us in moderation but determining how much one is getting is problematic.

  • no-dr-onboard 4 days ago

    There is a popular theory out in the fitness world that seed oils inhibit our skins ability to resist sunburns. Personally I’ve found it to be true.

amelius 6 days ago

Bremelanotide, a medication used to treat low sexual desire in women, has skin hyperpigmentation as a side effect. Could there be a connection?

https://en.wikipedia.org/wiki/Bremelanotide

  • adaml_623 6 days ago

    Interesting article. This sentence was interesting:

      Very early in the process one of the scientists, Mac Hadley,[15] who was conducting experiments on himself with the peptide melanotan II, injected himself with twice the dose he intended and experienced an eight-hour erection, along with nausea and vomiting.[13]
    • macinjosh 6 days ago

      I don't understand. Sounds like a typical Saturday night to me.

  • somedude895 6 days ago

    My bodybuilder friend used to inject Melanotan II (?) and would get super tan after just a couple days of summer. He'd also get wild random erections while on it. It's an anecdote, but the post title instantly made me think of that.

totony 6 days ago

"The questionnaire we used measured romantic passion, rather than physiological/sexual passion, due to institutional review board (IRB) ethical concerns regarding sensitive sexually oriented questions."

Curious about this. I understand ethical boards for psychological blind studies and such, but for questionaires?

  • xyzzyz 6 days ago

    Yes, it’s stupid. IRBs today are, on net, more of a detriment to science than a benefit. When they block a stupid voluntary questionnaire for being “unethical”, just imagine how much other useful science is not being done, because of concern lack of ethics of a similar grade.

    • freemint 6 days ago

      IRBs look like a net detrement to most studies because they are a mechanism to prevent really bad/unethical experiments in the far tails of distribution.

      If those extreme studies were to happen at a non suppressed rate we would be asking for IRBs and talking how science can't regulate itself.

      So IRBs might be effective but they suffer from the prevention paradox.

      • darkerside 6 days ago

        Would be interesting to see their reject pile.

        • freemint 6 days ago

          The mere presence of IRBs should discourage bad submissions however you are welcome to contact your local review board and ask for their juiciest rejects.

          • myself248 6 days ago

            I would follow this tumblr.

      • thrown_22 6 days ago

        IRBs are a net negative because really bad/unethical experiments are done with no oversight by private entities. Their only purpose is to keep ethicists employed.

        • klodolph 6 days ago

          This has got to be one of the worst takes on IRBs I’ve ever heard.

          The basic argument here is that rules are ineffective because bad actors ignore them.

          - Before IRBs, unethical experiments were done by professors and grad students with disposal to all of the resources they normally have.

          - People don’t always know what the ethical implications of their study is, or how it could negatively impact participants.

          - The IRBs are not there to stop research. They are there to help people figure out how to conduct research ethically.

          • thrown_22 6 days ago

            That's a very naive view of the expanding bureaucracy which must grow to meet the needs of the expanding bureaucracy.

            IRBs don't need to be ran by anyone more competent than a 5 year old to catch the cases you're talking about. What they have metastasis to today is just another part of the administrative industrial complex which has strangled academia.

            • freemint 6 days ago

              The question is how do we get 5 year olds between planning an unethical experiment (consciously or not) and the means to such experiments financed with tax dollars?

              Turns out 5 year olds might catch all the bad experiment but due to lack of understanding in the field they will also reject a lot of valid experiments. Domain experts and people who have thought a lot about ethics might have better false positive and false negative rates.

              Regulating constraints which impose a prevention paradox is though and is vulnerable to over bureaucratisation. I am unaware how this is handled but you told me nothing convincing which indicates that there is no back pressure limiting how much bureaucracy can be created by IRB.

            • klodolph 6 days ago

              > IRBs don't need to be ran by anyone more competent than a 5 year old to catch the cases you're talking about.

              Could you give some examples of what cases I’m talking about? I’m just dying to see what kind of straw man argument you’ve been building.

            • cycomanic 6 days ago

              Seriously if you think that IRBs are anywhere near the top 100 of things that are strangling academia I'd like your job. There are so many other issues that are so much more important that, let's fix those first.

        • matheusmoreira 6 days ago

          > really bad/unethical experiments are done with no oversight by private entities

          Yes. For example, every time we see someone here talking about A/B testing, they're talking about human experimentation. Do these humans buy more often when shown A or B?

          I consider it unethical as they don't even inform test subjects nor do they seek consent. Unfortunately, I seem to be a minority.

          I don't think this argument invalidates the concept of review boards though. If anything it supports their expansion into national or international law.

        • ttpphd 6 days ago

          I am grateful for the protection provided by IRBs and I understand exactly what kind of horrors they protect people from. They are an overwhelming positive force for good for science and society.

    • moron4hire 6 days ago

      I was supposed to get an IRB review for a graphics experiment I did in undergrad where I showed people static, non-animated optical illusions on a computer screen and asked them some questions about whether or not it gave them the impression of hills. (This was, like, 20 years ago.)

      Apparently there was some concern about inducing epileptic seizures. Not that there was any evidence that optical illusions, on their own, separate from the flickering of the computer screen, could cause seizures. But someone had the idea and then it couldn't be un-un-boxed.

      The IRB submission process would have been too long to finish the study by the end of the semester (by the time I found out about it). So I just... didn't tell anyone I had already posted the demo online, before I ever even learned that IRB existed, and had a bunch of people on a game development forum on which I was a regular go through the study.

      In my case, it was super low stakes. I mean, people into game development are subjecting themselves to the dodgy apps all the time. But when I tell this story today, there are two types of responses: those who have done academic research and laugh at my story, and those who haven't and start crying about "HuMaN eXpErImEnTaTiOn!!!"

      I should start putting that on my business card: "formerly engaged in unlicensed human experimentation."

      Who am I joking? I don't have business cards anymore. It's going on my Twitter profile.

      • tetrep 6 days ago

        There's similar issues with computer security and having projects reviewed before being shipped, with the classic story of people avoiding review because they didn't think they needed it at the start of their project (not that they're qualified to determine that) and by the time someone told them about it, it was "too late" and they'd miss important deadlines by going through the requisite review.

        The only sane solution I've seen to that is to make everything go through security review, even if the review is a simple "we don't need to review this." If everyone knows everything needs review, it makes it very hard to forget about it and incentivizes people to involve security folks with their projects ASAP in the hopes of getting review done early on / avoiding being blocked by it.

        You'll always need exceptions to the rule, so you can have some sufficiently high up VP or similar sign off on releasing things without review (and with the caveat that it's still going to get reviewed, it just won't block release), but that's a lot easier to manage than dealing with random developers deciding it for themselves.

        It also helps a lot to have a culture where developers learn about security too, but just like researchers and ethics, they'll have perverse incentives to downplay/ignore risks so you still need other, differently incentivized people, to enforce "checks and balances."

        It sounds like IRBs are not designed to review all or even most (animal?) experiments and I think that's unfortunate. It seems like a win for everyone if we get better ethics coverage.

  • pas 6 days ago

    https://www.cspicenter.com/p/its-time-to-review-the-institut...

    classic feature creep + bureaucratization (so it's now done by a special class of IRB administrators, not really by peers, etc)

    • klodolph 6 days ago

      I would normally be a bit skeptical of anything published by CSPI.

      • inglor_cz 6 days ago

        Given that American universities now routinely have a lot more administrators than teaching staff (still very untypical elsewhere in the world), wouldn't you at least agree that the bureaucratic bloat is real?

        This is, after all, what the students are paying in their tuition, which is becoming a major burden on the American middle class.

        (Ironically, "tuition" as a word promises that the money is mostly spent on teaching, not on administration and amenities.)

        There is a strange reluctance on the American liberal left to criticize greediness in academia or even acknowledge that such thing exists. Politically, I get it, the academia is overwhelmingly liberal-left, so there is an instinct not to alienate it. But there surely must be some upper bound to the growth of tuition costs, after which the burden becomes unbearable.

        • suoduandao2 6 days ago

          politically I think it's more that in America, administrative positions skew heavily towards the political left in or outside Academia. There's a whole theory of analysing American politics based on the idea that the 'professional managerial class' (i.e. salaried administrative types) have interests that are better taken care of by the democratic party and vote accordingly.

          I think the cognitive dissonance is more that administrative types want to think of their positions as necessary to the proper functioning of things.

        • magicalist 6 days ago

          > Politically, I get it, the academia is overwhelmingly liberal-left, so there is an instinct not to alienate it

          > Eschew flamebait. Avoid unrelated controversies, generic tangents, and internet tropes.

      • xyzzyz 6 days ago

        Why? Do you care to elaborate, or do you prefer to just cast vague aspersions?

    • UpstandingUser 6 days ago

      Sounds like the Iron Law of Bureaucracy is at it again.

sitkack 6 days ago

Could be a signaling behavior to encourage spring births. Does UVB peak in the middle of the summer? 9 months later is probably the best time to birth a child for that child's success.

  • newaccount74 6 days ago

    The study measures the effect in mice. Mice have a gestational period of a few weeks, so that's probably not it.

    • sitkack 3 days ago

      It works in mice as well, they just don't have to wait a winter cycle for gestation. They basically give birth instantly after mating. They would be making _less_ babies during the low UV months and peaking during the summer time when the living is easy.

  • jshprentz 6 days ago

    Gabriele Doblhammer and James W. Vaupel concluded that "month of birth influences adult life expectancy at ages 50+" in their paper [1] in the Proceedings of the National Academy of Sciences (PNAS).

    They tracked for 30 years the mortality of all Danes who were at least 50 years old on 1 April 1968 (about 1.4 million people born before April 1918). They also analyzed about Austrians with known birth dates who died between 1988 and 1996 (about 700,000 people born before 1947) and native-born Australians who died between 1993 and 1997 (about 200,000 people born before 1948).

    They found in Denmark and Austria that "adults born in autumn (October–December) live longer than those born in spring (April–June). The difference in lifespan between the spring and autumn born is twice as large in Austria (0.6 years) as in Denmark (0.3 years). ... We found the pattern in the Southern Hemisphere to be a mirror image reversal of that in the Northern Hemisphere." British born Australians were statistically closer to the Danes and Austrians.

    Their analysis eliminated three hypotheses for these observations: seasonal distribution of deaths, social factors related to seasonal distribution of births, and differential infant survival. Their analysis and other studies of birth weight data led them to conclude that "seasonal differences in nutrition and disease environment early in life [in utero and infancy] could explain the relationship between month of birth and adult lifespan." Over the years, winter and spring nutrition has improved, so "the relationship between month of birth and lifespan seems to be stronger among the older birth cohorts than among the more recently born."

    [1] https://www.pnas.org/doi/10.1073/pnas.041431898

    • SnowHill9902 6 days ago

      Hypothesis: people conceived from impulsive sex on Midsommar are more likely to have un-attending and less-caring parents, and possibly inherit lower self-control traits.

  • ilaksh 6 days ago

    That seems possible but also more directly winter may be a bad time to start a pregnancy.

    • techdragon 6 days ago

      Avoiding the birth of a child right before winter would be advantageous for its survival… winter being (on average, not all regions/locales obviously) the hardest month to survive evolutionarily speaking this would be a beneficial trait and be likely to stick around. Ideally you want your early hominid babies at the end of winter through spring and summer so at worst they are though the first few fragile months that put the most drain on the mother, before the harshest winter weather sets in.

      While not globally consistent due to regional weather differences it makes sense for there to be a broad average seasonal benefit.

      • littlestymaar 6 days ago

        Except those “early hominid” lived in Africa, which isn't known to be the place with the harshest winter. And the fact that humans living in temperate climates and humans in tropical areas belong to a single species makes me believe that adaptation to winter wasn't that big of an evolutionary factor.

        • yxhuvud 6 days ago

          Now you assume this wouldn't be something that is common for most mammals. In places where there is always sun there is no reason to evolve away people having more sex when there is sunny.

          Meanwhile here in northern Europe we get markedly more children during March-April. Which of course could be a sociological thing, or depend on something else, but still.

          • semi-extrinsic 6 days ago

            I believe the phenomenon in Scandinavia that more children are born in spring is partly due to families performing economic optimization wrt. timing of kindergarten and parental leave.

            • lotsofpulp 6 days ago

              April-May in the US has following benefits:

              -out of pocket maximum expenses are capped per calendar year. Typically, healthcare expenses for births happen in the latter half than former, and so you can potentially save a few thousand dollars, and even up to $17.4k (legal max). Post birth complications are plenty, and pelvic floor physical therapy does wonders. Not worrying about costs for these is a huge benefit.

              -new resident doctors start in June, so you have less risk of a brand new doctor in April/May when they would have had 10 months of experience

              -kid would be 6 months of age by winter season, so eligible for flu vaccine, and now Covid vaccine too during their first winter

              -lots of schools have hard cutoffs at Aug 31 or around there. Birthdays before then, kid is in school, and after that, kid has to wait another year to start school. This could mean 6+ months of fewer daycare expenses, easily worth $10k

  • littlestymaar 6 days ago

    As far as we know, humans are a tropical species, which means reasoning about summer and winter is likely to be more misleading than anything.

    • davesque 6 days ago

      Doesn't it seem like a common misconception that evolution takes eons? Without being an expert, it seems plausible that we've adapted biologically since venturing out from the tropics.

      • wongarsu 6 days ago

        The most obvious adaptation since venturing from the tropics is reduced pigmentation to adapt to less intense UV radiation. Nose shapes are also influenced by climate.

        The idea that we stopped evolving sometime before we spread over the globe is obviously false, with the number of adaptations that are plainly observable on the outside.

      • hackerlight 6 days ago

        But that "we" includes people that didn't venture out of the tropics, who presumably are impacted the same way by UVB, which if true would refute the hypothesis.

        • wongarsu 6 days ago

          At a glance the study doesn't seem to investigate that at all.

          The authors are from Israel, so I guess the participants are Israelis too. That's one of the more ethnically diverse places, but only 12% of Israelis are of African origin. Of course not all of Africa is in the tropics, but there are a couple of Asian Israelis who are from the tropics, so let's estimate it at about 12% with mostly tropical ancestors. That might just vanish within the noise of the data unless you specifically look at the correlation to ethnicity.

          • hackerlight 6 days ago

            That's why I said "presumably". If it turns out that a group of people who've lived in the tropics for the last 50k years do not respond to UVB in the same way, then the hypothesis isn't refuted (and indeed it is validated).

    • echelon 6 days ago

      > Humans are essentially tropical animals and are not equipped to deal with even mild cold. That we can live in cold climates is a result of behavioural adaptations such as wearing appropriate clothing and building shelters.

      So this is why I hate winters and don't complain when it's 90 degrees Fahrenheit outside.

      I would wear a jacket or hoodie in the middle of summer because of the office AC.

      I need to move to Key West.

  • INTPenis 6 days ago

    I was thinking along the same lines but also harvest for fattening up.

gregsadetsky 6 days ago

One of the referenced papers [0] concerning addiction to UV light (in rodents) is fascinating as well..!

“UV light is an established carcinogen, yet evidence suggests that UV-seeking behavior has addictive features”

“Opioid blockade also elicits withdrawal signs after chronic UV exposure”

[0] https://pubmed.ncbi.nlm.nih.gov/24949966/

  • lapsis_beeftech 6 days ago

    What might be going on here is that the UV induces radiation damage, which leads to endorphin release as part of the body's response to injury and pain. I have experienced this effect myself at times after getting a sunburn; the endorphins blocked the pain entirely and it was moderately euphoric. I know how dangerous sunburns are but if I was a rodent I would likely seek ways to repeat the experience.

derefr 6 days ago

Implying that a primary causal factor for globally-declining birth rates could be... increased adoption of sunscreen, leading to decreases in libido?

(I'm only half-joking; the countries that are most obsessed with keeping skin white — and so are likely the highest sunscreen users — are also the countries with the lowest birth rates.)

  • numpad0 6 days ago

    I don't get how reduced UV exposure is supposed to be more attributable to sunscreens than to office labors.

    Most industrial materials block roughly 100% of UV rays, except viewing windows which allows as much as 1%. Therefore, just staying in any modern building alone cuts down UV exposure by 99% at very least. There is absolutely no way some translucent face painting does that.

    • derefr 6 days ago

      People have been working white-collar jobs indoors behind UV-reflective windows for 50+ years now. Birth-rate decline — especially to below-replacement levels — begins much more recently than that; and is only happening in certain countries.

      The set of countries experiencing birth-rate decline is not 1:1 correlated with the set of countries with high/increasing white-collar employment; but, AFAICT, it is 1:1 correlated with the set of countries that have strong avoidance of tanning / strong interest in skin-whitening.

      • whyoh 6 days ago

        >but, AFAICT, it is 1:1 correlated with the set of countries that have strong avoidance of tanning / strong interest in skin-whitening.

        I'm not seeing that. The countries that are most into avoidance of tanning are probably in Southern Asia, or Asia in general. Their birth rates are not that low, with the exception of Japan, S. Korea and Taiwan.

        • derefr 3 days ago

          The middle-class urban populations of these countries really liking lighter skin doesn't imply that the country as a whole will have light skin, though. Achieving that also requires that most of the country be middle-class and urban — being in the set of people who both have time to take care of their skin, and don't spend all day working outdoors in the sun in a way which will unavoidably result in tanning no matter how much sunscreen they use. This is true in Japan / South Korea / Taiwan; but not in these other countries, yet.

          You can see it happening in China right now (which also culturally has a preference for lighter skin), as the last few decades of infrastructure build-up have led to a new generation whose parents are lower-class farmers but who are themselves middle-class white-collar workers. My hypothesis would predict a lower birth-rate among this cohort, while the previous generation's birth rate remains high.

      • bruce343434 6 days ago

        Isn't it a common phenomenon that smarter people have fewer children? Once you achieve high education people are more strategic about when, or if, to have children and how many.

    • csdvrx 6 days ago

      > There is absolutely no way some translucent face painting does that.

      Wow what a dismissive comment to chemistry and cosmetics.

      Just for fun, try take a pic of yourself with a UV camera (or just UV light with some phones), and you'll see it's translucent only to the visible spectrum: https://petapixel.com/2016/05/26/tiny-uv-camera-shows-youve-...

      • derefr 6 days ago

        One thing I've recently become curious about, is whether the "UV pigments" in sunscreens are color-fast or not; i.e. whether getting sunscreen on clothing gradually tints the clothing darker when seen in ultraviolet, in the same way that getting throwing a non-colorfast red shirt in with your whites will gradually tint them red.

      • numpad0 6 days ago

        The Sun Protection Factor(SPF) is defined "a measure of the fraction of sunburn-producing UV rays that reach the skin" when applied as instructed and only over a defined period, usually 2hr[1]. That means there is twofold difference even between a pane of glass(<1% whole body) and correctly applied sunscreen(~2% for 2hr @ SPF50), before taking walls into accounts.

        1: https://en.wikipedia.org/wiki/Sunscreen#Sun_protection_facto...

        • LorenPechtel 6 days ago

          This. Note that even single-layer garments generally don't have a protection factor of 100. Simply being outside in warm weather will give you more UV even if you use sunscreen perfectly--and I don't believe perfect use of sunscreen happens in the real world. I don't care how well you apply it, the protection will be degraded by movement. It will be degraded even more by touching things.

  • yjftsjthsd-h 6 days ago

    > the countries that are most obsessed with keeping skin white — and so are likely the highest sunscreen users

    Isn't it rather more about avoiding skin cancer?

    • deepdriver 6 days ago

      While American and European sunbathers tend to seek the perfect tan, many Indian and East Asian women avoid it at all costs, through sunscreen and a whole bevy of skin-lightening products:

      https://www.bbc.com/news/magazine-18268914

      https://www.sixthtone.com/news/1005927/chinas-quest-for-fair...

      Such standards of beauty are quite old and largely predate Western colonialism. My impression is that they were often linked to caste or class, where higher-class people spent more time indoors while lower-class workers spent more time out in the sun.

      This cultural difference is the source of much amusement for the Indian spouse of my European coworker. When they vacation in Europe all the ladies on the beach want to tan, and when they visit India it’s the other way around.

      • southerntofu 6 days ago

        > My impression is that they were often linked to caste or class, where higher-class people spent more time indoors while lower-class workers spent more time out in the sun.

        I'm no expert on the topic, but i heard people refer to this sort of social symbol and discrimination as "colorism".

        For anecdote, in France, "sang bleu" (blue blood) used to refer to the nobles and higher classes, as they didn't work the fields, and their thin and pale skin let see through the blue-looking veins. From what i hear, it appears before the revolution this biological distinction was formally racialized: the higher classes with their never-sighted "blue blood" was another "race" as the lower peoples whose spilled blood we could confirm was red.

      • samstave 6 days ago

        Yep,

        In many caste-esque societies, having a darker tone is a sign of having to work outside, thus of lower class.

        This happens a lot in the Philippines, for example. With a ton of skin lightening products.

        • rrrrrrrrrrrryan 6 days ago

          Being chubby and pale was desirable when the poor had to toil away outside and didn't have enough food to eat.

          Being thin and tan is desirable today when the poor have to toil away in offices and don't have enough free time to go to the gym or take vacations in warm places.

          • derefr 6 days ago

            Being tan is desirable for the upper class, because they're trying to avoid being seen as middle class "toiling away in offices", and don't particularly care about being confused for lower class.

            Being pale is still desirable for the middle class themselves, though, as they're trying to avoid being seen as lower class (tradespeople, farmers, etc).

            Also, thinness is actually a middle-class obsession, because it's the lower class who "don't have enough free time to go to the gym or take vacations in warm places." The upper class don't care what their bodies look like, as they all know that they and everyone else in the upper class can afford to "throw money at the problem" (plastic surgery et al), and so how healthy you look is no longer a good signal for how healthy you actually are. (Instead, they tend to judge your genetic fitness — when they care about that sort of thing — by the health of your lineage, going back several generations. Which is one reason royals/nobles make a big deal of keeping track of that.)

            • samstave 6 days ago

              >".... farmers..."

              [Dystopian Aside]: I have been saying for a very long time (rightly/wrongly), but always been laughed at; "In the future, the most valuable people will be farmers"

              I was laughed at.

              However, look where we are headed. Right now, today ; BGates is not only one of the most famous and richest people on the oblate spheroid, he is also the richest "farmer"[0] in the world.

              The "farmer" ([0]:pharm-er) who masters lab-grown civilization-supporting-scale sustenance production will be the richest in the galaxy.

              Ever try to corner the galactic wheat production in Trade Wars on BBSs in the 1980s? Yeah - we are at stage zero of seeing that in action, and it wont be pretty.

          • numpad0 6 days ago

            Chubby and tan signifies strength and wealth. Thin and pale yet rich is a contradiction, adds mystique and suggests power.

            • samstave 6 days ago

              Ha You physically fit, hardy to the elements, thin, muscular, used to hardship, leathered and hardened skin, emotions, grit and resentment who is only capable of using farm implements, what power do you have against me and my court of beautifully adorned elite, who weild the master-craft blades of our ancestors!? HA

              'Farmer-class': Well, we have awareness, darkness, and an array of farming tools as weapons, such as Kusari Gama (sickle), nun-chuck (rice thrashers), the modern police baton is a farmers implement...

              Also, we know how to fight in close quarters, such as your Rice Palace, and as such we have short, straight, nible blades and Iai KPIs show that our blades are superior in cramp enclosures, as opposed to your blades, which the curve is to assist in the blade length for the cut as you pull, however, in close quarters, your large exaggerated movements are a detriment....

              Also, We know that our blade is a tool thus, we will flick dirt at you with it, because you see your sword as an extension of your soul, and will not let it touch earth.

    • LorenPechtel 6 days ago

      Cultural expectations on tanning come down to signs of wealth.

      Industrialized societies most work is performed indoors, most people only tan during leisure time. Thus a tan is an indication of having leisure time and is looked upon positively.

      Societies that are not industrialized most work is performed outdoors, leisure is generally indoors. Thus the absence of a tan is an indication of wealth and is looked upon positively.

      Note that this lags behind reality, many places have industrialized but their perception of tans is still negative. My wife is Chinese and I sometimes joke that she's half-vampire because of how sun-avoidant she is.

    • arbol 6 days ago

      There are a whole host of benefits associated with sun exposure that are reduced by wearing sunscreen.

      “Avoidance of sun exposure is a risk factor of a similar magnitude as smoking, in terms of life expectancy.”

      https://www.outsideonline.com/health/wellness/sunscreen-sun-...

      • yjftsjthsd-h 6 days ago

        I'm open to the argument that it's wrong/irrational, but I would wager that - at least in the USA - people wearing sunscreen are doing it to avoid skin cancer more than to avoid tanning.

        • arbol 6 days ago

          "...skin cancer kills surprisingly few people: less than 3 per 100,000 in the U.S. each year. For every person who dies of skin cancer, more than 100 die from cardiovascular diseases."

          Personally, I'm from the UK and don't worry about skin cancer. If I was in Australia or some climate I'm not adapted for then I'd be concerned.

          • tremon 6 days ago

            kills surprisingly few people: less than 3 per 100,000

            Yet the impact on quality of life is huge. Using the same US numbers [0], comparing directly-attributable deaths against life years lost (disability-adjusted life years):

            - melanoma: 2.2 vs 64.8

            - squamous cell carcinoma: 0.8 vs 26.6

            - basal cell carcinoma: 0.2 vs 51.2

            [0] https://pubmed.ncbi.nlm.nih.gov/33852922/

            • arbol 6 days ago

              Fair cancer impact comparisons. But the point was that increased sunshine can reduce cardiovascular issues so you'd need to look at incidents and impact for heart attack, stroke, etc.

      • xcambar 6 days ago

        I am not certain how much credibility this publication deserves.

        It's not scientific by nature, it focuses on outdoor activities, which is only a tangent topic, the author has no bio, there is little to no bibliographic references.

        • sooheon 6 days ago

          The quotation is from a well known paper in the field cited over 100 times according to google scholar: https://doi.org/10.1111/joim.12251

          It was an observational study of 30k women over two decades, so very good statistical power.

          > As compared to the highest sun exposure group, the mortality rate was doubled (2.0, 95% CI 1.6–2.5) amongst avoiders of sun exposure and increased by 40% (1.4, 95% CI 1.1– 1.7) in those with moderate exposure. We found that the assumption of proportional hazards seemed reasonable.

          So at least among Swedish middle aged women, you are twice as likely to die if you avoid the sun, vs. if you are exposed more to the sun, controlling for factors like income, education, smoking, BMI, and exercise.

          It was not a RCT, but then almost no studies of all cause mortality are.

          A smaller case study of 500 melanoma patients (https://doi.org/10.1093/jnci/dji019) also found that "sun exposure is associated with increased survival from melanoma."

          I think sudden and extreme sun exposure, i.e. "staying in an office all year and then going on the beach for 9h on vacation" definitely requires sunscreen, but consistent and moderate sun exposure at a rate that your body can tan and adjust to is probably a net positive for everything from circadian effects to mood and mortality, even accounting for skin cancer risk.

        • arbol 6 days ago

          Perhaps I should've mentioned that this quote was taken from a research publication.

          "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.”"

    • nottorp 6 days ago

      I use it to avoid burns?

  • bushbaba 6 days ago

    If that’s the case then it’d come as a relief. But I doubt it. Realistically the fact wage to housing/health/education/childcare is a bigger contributor.

  • ipaddr 6 days ago

    It is probably birth control in the water supply that are causing birth rate declines.

  • dragonwriter 6 days ago

    > (I'm only half-joking; the countries that are most obsessed with keeping skin white — and so are likely the highest sunscreen users — are also the countries with the lowest birth rates.)

    Obsession with keeping skin white is not something I normally see associated with South Korea, Singapore, or Bosnia and Herzegovina.

    • shard 6 days ago

      Obsession with keeping skin white has been a major trend in Korea for a long time, have you seen all the weird hats and face masks that ajummas wear in order to reduce sun exposure?

    • Apfel 6 days ago

      Can't speak much for Bosnia but in most of South East Asia it's nigh on impossible to find any body wash, sunscreen or moisturiser without whitening products added.

    • tellmelies 6 days ago

      Have you ever tried to buy sunscreen in Asia?

mercy_dude 6 days ago

Question: how does sunscreen affect these outcome ? I have been in a UV-high indexed area for over 2hrs a day under sun and wondered if applying sunscreen everyday as I have to exposed parts such as arms and legs have negative consequences since all of them have benzene. Now this seems to be another reason for not doing so?

  • arbol 6 days ago

    Not directly answering your question but related: "early sunscreen formulations were disastrous, shielding users from the UVB rays that cause sunburn but not the UVA rays that cause skin cancer. Even today, SPF ratings refer only to UVB rays, so many users may be absorbing far more UVA radiation than they realize."

    https://www.outsideonline.com/health/wellness/sunscreen-sun-...

    • samename 6 days ago

      How can you know if it does both? Look for UVA on the bottle?

      • jvanderbot 6 days ago

        Zinc Oxide does. Kid sunscreen is almost always zink oxide to prevent hormone disruption from the nasty stuff they put in adult sunscreen.

        The term "broad spectrum" is used to denote UVA/UVB protection in the US, and is an FDA-regulated term.

      • mattlondon 6 days ago

        The UK - and I presume Europe - has a star rating for UVA protection in addition to SPF. Some details here: https://www.nhs.uk/live-well/seasonal-health/sunscreen-and-s...

        Tl;Dr - you want minimum 5-star 30 SPF for your daily cream.

        • collegeburner 6 days ago

          Do people actually use sunscreen every day? I wouldn't think a little sun (well before a burn) is that likely to cause problems?

          • Balgair 6 days ago

            I do. But I live at a fairly high altitude. If I don't put on the sunny, I'll get a bad burn in ~15 minutes of being outside. That's short enough that mowing the lawn or taking a walk will burn me. I got tired of always having a bright red nose or arms that just hurt. So, now I just have a bottle sitting by the door and schmear some on before going out. Also stopped wearing sunglasses, as they make burns worse. Again, I live at altitude.

          • FullStackAda 6 days ago

            I do. Aside from sunburns, sunscreen helps to prevent or delay photoaging and reduce inflammatory response to UV in the skin - meaning less acne, rosacea and hyperpigmentation. I use only European sunscreens with proper UVA protection.

          • mattlondon 6 days ago

            Yes the recommendation is SPF15 every day, even in winter.

            Many daily moisturisers will have at least SPF15 so it's no hardship since you're already moisturising every day anyway.

      • shard 6 days ago

        Look for PA+++ ratings. You might have to buy sunscreen made outside the US, such as sunscreens made in Korea.

  • sooheon 6 days ago

    UVB exposure -> p53 activation -> downstream sex hormones upregulation is hypothesized to be mechanism, so sunscreen that blocks UVB will probably reduce the effect.

    This study is part of an interesting trend I'm seeing of studies finding beneficial health effects to well timed, full spectrum sunlight exposure. The circadian benefits of seeing early morning sun every day (and darkness every evening) are well known. What's more surprising is that even UV exposure is not purely negative, and in the context of sunlight in moderate amounts (not to the point of acute sunburn) may be beneficial for health:

    https://doi.org/10.1093/jnci/dji019 finds that high intermittent sun exposure actually decreases melanoma lethality. I.e. those who avoid the sun die more from melanoma.

    https://doi.org/10.1111/joim.12251 found in a study that followed 30k women over 20 years that more sun exposure was associated with reduced all cause mortality. I.e. those who avoid the sun, apply more sunscreen die more in general.

Khelavaster 6 days ago

This isn't big news at all.

Melanocyte-stimulating hormones have been known to stimulate sexual behavior since forever. Melanocortin receptors directly modulate sexual behavior.

Melanocyte-stimulating hormone production is boosted by from inflammatory effects of UV damage. This has been known forever, too.

  • AuthorizedCust 6 days ago

    > boosted by from inflammatory effects of UV damage

    That wording supports a notion that the boosting is to encourage the most essential activity of a species—reproduction—in the face of potential harms that may shorten the opportunity for that activity (cancer-induced final exit).

    That said, I’m aware of counterarguments to the simplistic takes on “sun bad” messaging and think they have merit. Not trying to open a debate on the latter, just clarifying that I’m not trying to grind an ax with the first paragraph.

    • ramblerman 6 days ago

      That seems a bit simplistic of an interpretation when there are no similar effect for dehydration, hunger, loss of a limb, or other potential harms.

      Many animals are seasonal. And extra sun exposure might indicate a good time to mate (spring/summer)

      • AuthorizedCust 6 days ago

        Your example harms have an immediate effect. Sun exposure usually does not.

    • treeman79 6 days ago

      Sun exposure causes a severe inflammatory exposure for me. Spent a day at the beach and it was 7 months of burning nerve pain before I got it calmed down. Side effect of autoimmune Sjogrens.

      I don’t go out if UV is above a 2 anymore.

    • whatshisface 6 days ago

      There's no way that we evolved to chemically respond to an effect that takes fifty years to happen.

      • AuthorizedCust 6 days ago

        Evolution is a long tail game. Over eons, any mutation conferring an increased likelihood of sustainable reproduction can “win”, including this one.

    • sdwr 6 days ago

      Thats what came to my mind too.

  • gavinray 6 days ago

    Anyone who has taken Melanotan-2 or PT-141 could tell you this ;^)

  • beowulfey 6 days ago

    Thank you for the additional info. I certainly found it to be big news.

taylorius 6 days ago

Interesting. A possible mechanism for the legendary passion of people from "hot blooded" countries?

  • ETH_start 6 days ago

    If anything, people who originate in cold climate countries visiting hot-blooded countries would receive more UVB due to less skin melanin, and thus be more hot blooded than the natives of hot blooded countries when interacting with them, and vice versa, so that would't explain the association.

    • tcldr 6 days ago

      Ah, the ‘Brits Abroad’ phenomenon finally explained.

      • Jugurtha 6 days ago

        Something that fascinated me with Russians is how they go out of their way to get every bit of sunlight. I mean, they act like sunflowers, even standing to face the sun and open their arms on the beach, and orienting themselves towards it. They'll go to the beach at ungodly hot hours and stay under the sun, in Tunisia, during summer!

        It is amazing because I'm really dark and dark skinned, I'm also native of the region (Algeria), and even then, I'll protect myself and stay in the shade because I'll get sunburnt very easily if I don't take precautions. They're fair skinned and they're not as cautious. It's just incredible.

        • shipman05 6 days ago

          Anecdotal, but not all fair skinned people react the same to sun. My wife and her Polish-descended family get a nice golden tan from sun exposure. My English-descended family and I just burn instead. But we all look equally pale during the winters.

          Russians are ethnically much closer to the Poles

  • thrown_22 6 days ago

    All that's racist is new and progressive again.

    I'm still waiting for someone to explain the difference between colored people and people of color.

qvrjuec 6 days ago

The melanotan peptide's effect on melatonin production and libido is super interesting considering this finding

water8 6 days ago

Or maybe tan people just look more attractive and get more attention

  • felipelalli 6 days ago

    Or just people that work in field don't watch so much porno.

gizajob 6 days ago

I could tell Aussie girls were different.

amelius 6 days ago

Would it make sense for a curious hacker to try out a narrowband UV-B lamp?

https://www.proflamps.com/datasheets/Philips%20Phototherapy-...

  • sooheon 6 days ago

    There is a corner of the biohacking sphere for everything, including this:

    https://getchroma.co/product/chroma-d-light/

    https://www.sperti.com

    I never bothered with a device because we have the actual sun for free, and the potential for misuse is enormous -- it's trivial to accidentally blind yourself.

    • amelius 6 days ago

      Thanks. I was thinking of mounting a light onder my table, so the skin in the legs can pick up the UV-B, thereby reducing safety risks and also distraction. It would be interesting to see if a day of programming could give me the same benefits in terms of well-being as a day surfing waves :)

seydor 6 days ago

Time to invest in that maker of UVB bedroom lightbulbs

MrYellowP 5 days ago

Yet another piece of knowledge everyone should already be aware of, but apparently isn't.

andrecarvalho 6 days ago

I’ve always joked that in summer I felt more “horny”. Guess I could’ve been into something.

Zenst 6 days ago

Certainly does corelate and will attest one's libido does increase in the Spring.

lettergram 6 days ago

Seems this was only done on mice. Wouldn’t it be easy to evaluate (statistically) on males. Basically measure testosterone levels of out door laborers and indoor laborers.

Then as a follow up have the indoor laborers go outside for 1 hr mid-day or something for 12 weeks and measure the effect.

  • sooheon 6 days ago

    If you skim the paper you will see they did multiple studies, including in humans. Including epidemiological studies and interventions like you mentioned. Which is why this is a well conceived paper, imo.

    Testosterone is increased for men living in areas with high UV radiation, but only during summer time.

    Proteins upstream of sex hormone production were upregulated after just a single day of 25m of bright midday sun exposure in both men and women.

  • leni536 6 days ago

    > Basically measure testosterone levels of out door laborers and indoor laborers.

    This is very susceptible to various biases.

    • xnx 6 days ago

      E.g.physical activity levels, body fat %, etc.

immigrantheart 6 days ago

Not trying to be racist, but does this mean darker skinned people (caused by sun burn) are sexually more active?

  • SamoyedFurFluff 6 days ago

    Sun burn doesn’t cause darker skin. Also being tan from sun exposure doesn’t have much to do with race. Melanin in the skin functions as a protectant against UV rays, so you would actually expect paler people to have more reaction to UV simply because they would have more exposure.