Time to sunburn (opens in new tab)

Sure, they are an adaptation. One that's best avoided _while you can_

Every time you get a "sunburn" and your skin turns red? That's DNA damage. The body is good at repairing that, but not perfect. Best not to take damage in the first place. And if you do, to at least reduce the total radiation amount.

We shouldn't be singling out people based on their appearance of course. But there should be more awareness that skin damage is cumulative, and skin should be protected as much as possible.

I regret not having done so when I was younger. As much as I hate sunscreen.

I don’t know much about the process but always classified it myself as damage/scars. Though I could see calling non-sunburn induced freckles scars or damaged skin (or undesirable) as being inaccurate and just insensitive to people born with freckles.

For example we of course have these types of “glasses” for infrared which is fine for humans because we give off significant quantities of infrared radiation, but lesser known is we also emit light in the visible spectrum, it’s just not enough intensity for our rods/cones or inversely our rods/cones are not sensitive enough to observe the visible light we emit. Anyway your invention would be cool, even if it just ratcheted up the existing visible light spectrum enough we could see ourselves glowing in the dark…it would give people a new appreciation for Carl Sagan’s quote that we are made of stardust.

Sunscreen definitely prevents sunburns, and almost certainly delays visible skin aging/weathering. Those may be enough benefits for some people.

But the people/populations using more sunscreen are also having more skin cancer. Some theories compatible with these observations are:

• While preventing sunburn pain, sunscreen doesn't prevent the actual cancer-causing skin damage - and thus by allowing more time to be spent in the sun, actually worsened skin cancer rates. (This may have especially been a problem for the 1960s-1990s, when it was thought that only sunburn-causing UVB contributed to skin cancer - so sunscreens only blocked UBV. That encouraged increased exposure to the mostly-unblocked UVA, now understood as an equal contributor to skin cancer. More recent sunscreens block UVA as well.)

• Known carcinogens commonly used in sunscreens, or present as contaminants, are actually causing increased rates of skin cancer.

Anyone whose true worry is skin cancer should use shade & limited times of exposure - not sunscreens. (Ensuring a spaced-repetition of gradually-increasing exposure, to develop a natural tan without ever reaching a peeling burn, is also likely naturally protective against skin cancer.)

Further, while endogenous Vitamin D production relies on sun exposure, and low Vitamin D is correlated with health problems, oral Vitamin D supplementation may not replace all the benefits of sun exposure.

Generally, large population studies show positive effects of moderate sun exposure on many health outcomes, including overall longevity, heart disease, and non-skin cancers. Meanwhile, Vitamin D supplementation studies have usually not found that such supplementation alone reverses the correlations of many diseases with low Vitamin D. Thus, Vitamin D may not be the only mechanism by which sun's benefits are achieved.

So rigorous sun-exposure-minimization, even if it does reduce (often benign or increasingly survivable) skin cancers, may increase overall mortality through higher heart disease & other cancers. (Your HHS report mentions 9,000 skin melanoma deaths per year. There are 650,000 heart-disease deaths and 600,000 other cancer deaths.)

Get sun. Use shade, clothing, & timing to ensure it's not so much sun that you peel. Use sunscreen sparingly, only when you can't moderate sun exposure other ways.

UVA has also been shown to lower blood pressure. This is probably the result of UVA causing the release of nitric oxide from skin stores, which promotes widening of blood vessels. It also acts as an antioxidant to prevent damage to cells.

People who don’t get enough sunlight have altered cellular defense mechanisms that predispose them to excessive inflammation, which can result in autoimmune diseases.

One could argue you can supplement to replace VitD, but are you supplementing your children? From what age? How regularly? What's the quality of the supplementation? How do the poor maintain access to supplementation?

Then you run into the problem that long term, large(r) doses of Vitamin D causes kidney problems.

A study ( https://pubmed.ncbi.nlm.nih.gov/21430082/) found an association between low vitamin D levels and the development of type 2 diabetes. For every ten-unit decrease in blood vitamin D levels, we found a 10% increased risk of developing this form of diabetes over the following five years. when they gave supplements of vitamin D to patients with low vitamin D levels who were already at risk of developing diabetes, there was no overall improvement in their sensitivity to insulin. Nor was there a change in their blood glucose levels compared with those given inactive tablets.

I'm betting, not just in this case, but the act of your body making it's own VitaminD creates benefits we are not yet aware - that oral consumption of a pill isn't going to compensate for.

nevermind MOST of VitaminD pills use soybean oil or some other horrible Omega-6 ridden, cheap seed oil as it's delivery method.

Outside time in the sun is helpful in ways not tied to VitD, as well. circadian rhythms are regulated by bright light exposure. You can't get these lumens by waking up and sitting inside all day. The heat from the sun is capable of reducing physical stresses on the body’s cells and by increasing heat production.

Another important potential effect of sunlight is UV-induced suppression of the body’s immune system. Solar radiation does this by altering the activity of the white cells involved in turning on the body’s defence mechanisms. This may seem like a negative, but it's vital for people to reduce inflammation and when considering how the earth's population spreads out autoimmune disorders (higher percentages the more you get away from the equator), this may be a secondary factor on top of VitaminD.

IMHO -

people need to find a balance with sunscreen and sunshine. if you know you're going to risk a burn, put it on and reapply when necessary.

if you're worried about cancer, eat some cruciferous vegetables regularly to make sure you get lots of sulforaphane which protects against skin cancer. Get regular derma checkups.

but when looking at auto-immune issues (that once you have one, your supplementation isn't going to undo it), the depression issues, and so forth - isn't worth skipping out on sunshine.

Skin cancer may be the most preventable but it's also a fairly unlikely cancer, as far as cancers go - and while it's one of the scarier cancers, catching it early with derma appointments is key to survival. Catching it early has a high survival rate.

An auto-immune issue, on the other hand, will shorten your life and make you suffer along the way, increasingly, for the rest of your life. It's not just a death sentence. It's a slow-slog through hell on the way there. Most people never go into a permanent remission of Ankylosing spondylitis or MS. It just slowly destroys you, it handicaps you, and then it kills you. And along with all that suffering, is your kids, parents and partners suffering right along with you. Yay - therapy sessions for everyone.

It's not just auto-immune issues. Depression, anxiety, even certain cancers themselves all have some relation to low vitamin d.

IMHO - sunlight needs to have it's saturated-fat moment where we realize that a lot of the fear mongering simply wasn't warranted. And that the cures for some diseases end up being the catalyst for many others that are far more likely.

How many people are afflicted with an autoimmune issue? how many with debilitating depression? Compare those numbers to skin cancer. Compare the deaths. Compare the suffering.

Then try to find a balance.

What counts as massive?

And is consuming massive amounts of Vitamin D necessary to prevent deficiency?

Buy a higher quality sunscreen (there are multiple reddits for this exact purpose) and you will not get poisoned by benzene and it won't be greasy and smelly.

> It's a common misconception that speed determines how fast you get to your destination, but actually distance also matters. So speed does not reflect time to destination. Instead, speed lets consumers compare the level of relative quickness and that 60mph is quicker than 6mph.

Obviously we need to hold other factors constant. It's not a useful point in when talking about speed and I don't see the point in talking about SPF. And it certainly doesn't mean that time to destination is inversely proportional to speed.

No you can't. Or rather, you shouldn't. If you have more melanin you obviously have more protection. But your skin will still get damaged by a midday sun, and it will age faster than normal.

This misconception that darker skin does not need protection is really harmful. Maybe that allows you to skip sunscreen for short periods of time, or in early morning, late evening. Not midday, unless "some sun" means just a few minutes.

Fast forward a few years and I'm back to where the first few days mowing the yard will see me get burned. Give it a few weeks and I can go longer without a hat.