yes, but my comment was on somebody trying to somehow support how unhealthy it supposedly is with something sciency sounding that is just completely wrong and, as somebody above already pointed out, similar to saying stuff like water is a dangerous oxide or some such. It does the very opposite of being scientific support, namely, it discredits. Let us all stick to what we actually understand when arguing.
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The point was to reframe the typical logical fallacy that “sun healthy because natural” with the scary unnatural sounding “nuclear fusion reactor”. Regardless UVA/UVB isn’t healthy and will age your skin, as long as you supplement vitamin D.
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Is it not possible, or even likely, that a lot of the benefit of being in the sun has nothing to do with the effects of different portions of the electromagnetic spectrum on your skin, but is rather the result of the effect on your mood? Basically a “placebo” effect? I have no illusions about the harmful effects of UV, and I am very diligent about wearing sunscreen, covering up when possible, and seeking shade when possible. But I love to be outside, like many other people, and can sometimes experience mild seasonal depression in the winter.
I think it’s far more likely that just “being in the sun,” the experience, is the important part and that you should continue to protect yourself from UV as much as possible.
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Bright light (10-50x brighter outside than inside) has a mood boosting effect and is used to treat some types of depression, and people like warmth. It has nothing to do with UVA/UVB and you don’t need to expose yourself to that. Infrared goes right through clothes.
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NIR (700 to 2500 nm) transmittance for a white cotton T-shirt at 800 nm is 35-45% like with visible red light, 20-25% at 1000 nm where C-H bonds (cellulose) absorbs, and below 10% beyond 1500 nm, mostly due to residual water. Look through a white T-shirt and see how simply having a colored shirt already lowers transmission. You are talking about denim and hats.
That’s not a graph of sunlight and CVD, there’s no adjustment of confounding factors, so it could be infectious disease, temperature, etc.
UV exposure without sunburn still cause lentigo maligna melanomas according to Avi, and I think skin aging as well.
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The full story:
A growing body of research hints at health benefits from sunlight that go beyond just those offered by vitamin d. These include protections against heart disease, cancer and autoimmune diseases. A study published last year, for instance, examined medical data from 360,000 light-skinned Brits and found that greater exposure to uv radiation—either from living in Britain’s sunnier southern bits rather than the darker north, or from regularly using sunbeds—was correlated with either a 12% and 15% lower risk, respectively, of dying, even when the raised risk of skin cancer was taken into account.
That fits with the results of another big study published a decade earlier. Led by Pelle Lindqvist, an epidemiologist at the Karolinska Institute in Stockholm, it followed 30,000 Swedish women for 20 years. It likewise found that, even after correcting for things like age, wealth and health, sun-seeking behaviour was associated with a lower chance of death from all causes. People with the most sun exposure had only half the risk of dying compared with those who had the least exposure.
“The big picture is that the benefits of sunlight outweigh the risks—provided you don’t get sunburnt,” argues Richard Weller, a dermatologist at the University of Edinburgh and one of the authors of the British study. Drs Lindqvist and Weller are two of the 17 scientists who also wrote a review paper, published in June, which urged public-health bodies to pay more attention to the growing evidence for the beneficial effects of uv radiation.
In 2009 a group of researchers based in Germany showed that uv irradiation converts chemicals in the skin into nitric oxide, which then makes its way into the blood—and that whole-body exposure caused a quick and substantial drop in blood pressure.
chart: the economist
That throws suggestive light on existing data showing that blood pressure tends to rise the farther from the equator you go. One 2017 paper found an increase of roughly 5mm of mercury (the units in which blood pressure is measured) for every thousand kilometres north of the equator. High blood pressure is a risk factor for heart disease—and death rates from heart disease in high-latitude countries also show a striking seasonal pattern, being highest in winter and lowest in summer (see chart). Some of that is down to colder weather, changes in diet and the like. But some researchers wonder if at least some of it could be down to lack of sun, too.
Another intriguing line of evidence concerns uv radiation’s effects on the immune system. For multiple sclerosis (ms), it appears to offer relief (like high blood pressure, ms seems to be more common in higher latitudes). Some scientists are exploring whether uv’s effects on the immune system might also improve its ability to combat cancers. In work that is currently unpublished, Drs Virós and Weller have studied a specific immune mechanism (unrelated to vitamin d) in both people and lab mice that may reduce the risk of cancer spreading to other parts of the body.
Other studies report an association between sun exposure and lower rates of diabetes (with evidence from mice once again implicating nitric oxide). A lack of sunlight is thought to be an important reason why, in some Asian cities, more than 80% of teenagers now need glasses. Bright light—of the sort that is hard to generate indoors—appears vital to regulate the growth of children’s eyes.
Read the full story: The health benefits of sunlight may outweigh the risk of skin cancer (Economist)
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I think we’ve discussed similar studies before and I think there was a lack of controlling for confounding factors, either way having broad spectrum UV exposure seems premature.
The health benefits of sunlight are likely from the infrared and near-infrared parts of the spectrum, not UV. Medcram has some great YouTube videos on this subject.
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Newer study showing more benefits of sunlight in case it hasn’t been posted yet
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“associated with”, not showing. We should at least expect an adjustment for serum vitamin D if the effects are supposed to be independent of that, which might be the case for e.g infrared and bright light.
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