Exposure to the Sun's UV radiation may be good for you

This always strikes me as a tough discussion. With the odd hostility between the two extremes of "all sun is bad exposure" and "you should get more sun." With the later taken to be "all sun is good exposure."

Just observing a typical yard, it is easy to see that grass can both have too much and too little sun. Indeed, cover it up and it will die. Expose it to direct sun all day for several days with no water and it will similarly die. (Well, not similarly, it will die in a different way.)

I realize we don't photosynthesize, and burning is clearly bad for us. But I don't understand why people seem so resistant to the idea that some sun is probably beneficial.

I also realize that literally "basking in the sun" is almost certainly taking it too far. :(

Reducing everything to “good for you” or “bad for you” is the media’s favorite game. Nuance is hard, so reducing complex topics to extreme statements makes them easy to digest. It also creates an opportunity for them to manufacture debate whenever a new piece of information comes out that doesn’t fit into their self-created bipolar conception.

As always with these topics: UV exposure isn’t something that can be reduced to “good” or “bad”. Both extremes of complete UV avoidance and excess UV exposure have consequences.

What people frequently miss on this topic is that sunscreen isn’t a 100% effective UV blocker. People who cover themselves in sunscreen and then spend significant time outside are receiving some UV exposure. This fact is lost on many people, which is why skin cancer rates can be higher in people who use a lot of sunscreen. Sunscreen enables people to spend more time in the sun and be less covered, which can paradoxically lead people to get more UV exposure over more of their body than, for example, the person who works outside M-F but covers up with long sleeves, hats, and pants (like you will see in yard work crews, construction workers, and other trades).

These headlines are difficult because some people read them as an invitation to stop using sunscreen but continue their old habits, pushing their UV exposure deep into the high risk region of the benefit-reward curves.

I'll take the UV rays over a bunch of smelly, synthetic goop all over my skin. I also see people go from not seeing the sun in months to full, 1pm exposure for hours, then they get roasted, then they're in pain, then it takes weeks to heal, then they do it again. Or they'll start slathering on an absurd amount of sunscreen, the summer months go by, and they look just as sick and pasty and unhealthy as they did last year, as if they never went outside.

You've got to build intuition around how to get sun: what's your current skin tone, how much sun you've had recently, what it feels like to get an appropriate amount of sun vs. get burnt, the time of day, elevation considerations, whether you're going to be in the sun again tomorrow or all week after a lot of exposure today, if you're getting more direct sun on key areas like your neck and nose and ears, or whether you've got full body exposure. The more time in the sun, the more you understand how to behave, how to protect yourself, how to get what you need to feel good.

Most people pay no attention to how they feel day-to-day. They never learn what it feels like to eat a nutritiously dense meal, or what being fit feels like over the long term. It's the same with sun exposure: if you don't pay attention, you'll never learn.

> According to Richard Weller, who co-led the study, most uv exposure guidance has thus far been firmly focused on preventing melanoma skin cancer. But, he says, “Many times more people die from other cancers and diseases. We have to think about how uv radiation could help them avoid illness.”

> The exact mechanism whereby uv light might lengthen lives is unknown. The authors, for their part, believe part of the explanation may lie in vitamin D’s ability to boost the immune system and improve bone health. They also point to nitric oxide, a potent blood-vessel widener capable of reducing the risk of cardiovascular disease.

The article is about a new paper in the journal Health & Place. That paper is open access and can be found at:

https://www.sciencedirect.com/science/article/pii/S135382922...

I've started to ignore studies these days that contradict how most humans would have lived, for most of humanity. Most humans would have had plenty of sun exposure and genetics would have adapted accordingly. I'll seek as much sun exposure I can on work days, but will never sun bathe for hours on end.

As I posted in the dupe of this -

this article is specifically about regions in “low” UV latitudes, with the actual subject being from the UK. Accounting for UV intensity of your home country is crucial.

Don’t just go out and frolic without precautions just because a study from the UK found sun exposure was good. Their sunlight isn’t built the same.

Mid day UV index in SF is 9 as I type. Compare what the paper says about the UK UV index:

“ The UV index [in the uk], which measures the erythemal intensity of sunlight, rarely exceeds 6 (where 3–5 is classified as moderate and 6–7 high)”

Make good decisions people! I got some sun when the UV was 2 early in the early morning. Now it’s 9 at midday. All sun is not equal.

This reminds me of the story of the Taiwanese radioactive homes, where 2000 homes were built with radioactive materials. There was a prediction that a lot of the inhabitants would die of cancer, and that didn't really happen.

https://www.todayifoundout.com/index.php/2020/12/the-curious...

This is probably even more complex than "The dose makes the poison". UV has some benefits and other known drawbacks (e.g. skin damage and cancer).

there's a popular trend that has been gaining momentum over decades that has people so disconnected from reality that they think a pill can replace proper diet, exercise, and in this case, the sun.

there is an obesity epidemic in this country at the root of many ailments (inflammation is the root of many diseases) and you have politicians pitching policies about bringing the cost of "drugs" down to treat these ailments but we have no mainstream leaders with mainstream policies advocating for health and fitness to fix the root issue.

we're going in the wrong direction and something has to change.

"Avoiding Sun as Dangerous as Smoking"

https://www.medscape.com/viewarticle/860805?form=fpf

Anecdotal, but the parts of my skin that see more sun exposure (forearms) look healthier compared with parts that are more covered (upper arms). I wonder if maybe gradual sun exposure starting from spring and increasing towards the summer is healthier compared to sudden intense tanning of the area that is otherwise constantly covered by clothes.

Would note that full-spectrum light penetrates thin layers of clothing such that you can still yield some benefits being outside fully clothed, with mitigated risk. Also, even with sunscreen you'll synthesize some vitamin D. You'd have to really lay it on thick over all of your body to meaningfully prevent that, and it only lasts for a limited time anyway.

On sunscreen there's talk about non-mineral ones having compounds that traverse the blood-brain barrier, but not much to suggest it can be dangerous. Since mineral sunscreens are oilier, my approach is to slather that type on my body, and use an alternative for my face using a light amount.

Let’s imagine that exposure to UV gives you more statistical QALY than melanoma and skin aging remove. I believe this is false but let’s imagine it’s true.

Okay but there’s many other things that also give you more QALY, things that don’t increase your risk of a horrible disease or looking like a prune when you’re 40. Maybe we should do those things first and only come back to double-edged life extension techniques when we’ve completed all the benign techniques.

After all, caloric restriction also increases lifespan, but the cost is so high in terms of life enjoyment that few would be tempted. There’s more to life than time spent living.

I think you can look into what humans desire for their ideal vacation places. The subconscious guides the conscious. This usually involves a sunny beach and water. Or at least a pool. Tropical fruits for breakfast and eggs is kind of a hotel standard for a reason too. Good nutrition and an a fun adventures day. Kind of polar opposite of dark depression.

Not too soud woowoo, but people with good vibes and sunny energy is what you should seek too.

For average office worker, during regular week it probably makes no sense to avoid exposure. On other hand sun bathing or tanning is probably not good for you either.

Sensible moderation makes most sense to me. If you are extended periods in sun cover yourself or use protection. But no particular need to avoid it in short periods.

From the point of view of evolution the sun is a fact of the universe and it would have adapted numerous processes to rely on its presence. That does not mean the sun is safe however. Skin color variance so closely tied to geographic location indicates that there is a very delicate balance there.

It might not be UV exposure that helps though. The sun has a bunch of other wavelengths of light as well. There's red light therapy that might have positive health effects and you certainly get that from the sun as well.

> Someone living in Truro, for example, in the south of Britain, would on average experience about 25% more solar shortwave radiation (a measure that includes UV, visible and some infrared light) in a year than someone living in Glasgow or Edinburgh, which are much further north.

I'm surprised that the difference is that big, given that the latitude difference between these is actually relatively small. If this difference is correct, is it really just due to the north/south distance, or is this more about weather differences, or is there some other non-obvious factor?

I think it’s pretty obvious from our evolution that we need some UV but not too much. In Africa, where we got a lot of sun, we evolved darker skin to prevent damage, but in the more norther latitudes, our skin tones lightened to take advantage of the otherwise insufficient sunlight.

I feel like a good rule of thumb would be, if you’re tanning, your body thinks you’re getting too much sun exposure for your current skin color.

Reminds me of people paying for radon exposure:

https://www.mdpi.com/1422-0067/22/1/316

https://www.youtube.com/watch?v=zZkusjDFlS0

Sun exposure has been inversely correlated with depression, and frankly depression by itself is worse than all the negative effects of UV I'm aware of combined.

Discussion of the actual paper: https://news.ycombinator.com/item?id=41302103

Perhaps because bacteria have no nucleus to protect their DNA and less DNA-damage repair mechanisms?

too much is bad, too little is bad, these doctors are not helping very much.

♫♫ Follooooooow....follow the sunnnnnnnn ♫♫

Note: preventing photo aging by limiting exposure to UV, is currently the single biggest thing you can do to slow [an aspect of] visible aging.

tl;dr: Some sun is good. No sun, or too much sun, is bad.

This advice will probably never change, regardless of qualified studies.