Skin exposure to UVB light induces a skin-brain-gonad axis and sexual behavior • Hacker News Board

Re: Skin exposure to UVB light induces a skin-brain-gonad axis and sexual behavior

#161

Post by no-dr-onboard » Mon, Aug 08, 2022, 3:20 PM UTC

MaintenanceMode wrote: post #89

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 outdo…

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.

Re: Skin exposure to UVB light induces a skin-brain-gonad axis and sexual behavior

#162

Post by hh3k0 » Mon, Aug 08, 2022, 4:45 PM UTC

no-dr-onboard wrote: post #160

vostok wrote: post #152

Earlier quoted context omitted.

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.

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

That's what I thought, too.

I mean, just google "Zuckerberg sunscreen".

Re: Skin exposure to UVB light induces a skin-brain-gonad axis and sexual behavior

#163

Post by sitkack » Tue, Aug 09, 2022, 1:07 AM UTC

newaccount74 wrote: post #52

sitkack wrote: post #21

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.

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

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.

Re: Skin exposure to UVB light induces a skin-brain-gonad axis and sexual behavior

#164

Post by derefr » Tue, Aug 09, 2022, 4:21 PM UTC

whyoh wrote: post #63

derefr wrote: post #27

Earlier quoted context omitted.

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 correlat…

>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.

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.