This is not even remotely surprising to me. I've always been a bit skeptical of "the sun is evil" (and got even more skeptical when I was told I should wear sunblock inside!) and ensure I get 20 minutes full body exposure daily in the summer. Anecdotally, I can tell a general difference in my mood and sleep during periods where I get adequate sun vs. when I'm not (and I supplement vitamin D when I'm not).
While I am a big fan of the scientific method, it is difficult to do studies that don't have lots of confounding variables in this area, so when in doubt, use common sense is my rule. We evolved with the sun, so the most likely probability is we have at least some defense to it, and more than likely we evolved so that at least some exposure has benefit.
A lot of the "sunscreen inside" people are those trying to maximize their visible skin health and beauty. If you don't care about your physical looks, as least above all else, I imagine the trade off to getting regular direct sunlight is well worth it.
But it is fairly intuitive that sunlight's ultraviolet radiation at any strength is going to degrade your skin over long periods of time.
Could you link to studies backing up your claim about 'visible skin health and beauty'?. I have searched for these a lot, but I cannot find thorough literature study type of research about this.
Except for the 'sitting in office all year and then sit in the sun for two weeks straight and get 14 sun burns is not good, so you should use sunscreen' message, which is not very helpful and could conclude also that one 'should expose to sun moderately, e.g. at least an hour a day if possible'.
Photoaging is the term and a quick search yields a few studies. Ex: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8802961/.
And anecdotally, I never used sun screen and was exposed to a lot of sunburns in the Mediterranean climate. My skin is visibly older and more wrinkled than my peers who used skin protections. My back is full of freckles and dermatologist said this is due to sunburn. I guess sunburn doesn’t need a lot of studies to show it’s very damaging to the skin?
That is kind of my point. Sun burn is not good. But without sun burn? The article you sent doesn't make clear whether photoaging always happens, or only on sun burn or other high doses of exposure.
Not sure about studies, but in a recent deep dive into skincare, all the YouTubers I watched considered it a basic fact, so the assumption is definitely prevalent. Studies would most likely be sponsored by skincare companies.
There's also that picture of the trucker that shows the damage the sun did to the left side of his face after 28 years of driving a truck. Google "picture of trucker with sun damage"
Maybe the trick is to spread sun exposure across the body rather than mostly let our limbs and face take most the sun. Protect those areas, but get fuller body sun more often. The parts of my body on the boundary between heavy exposure and no exposure seem relatively okay. They have a slight freckle-ness to them, but arguably acceptable. (I'm not young; time-tested.)
While I am a big fan of the scientific method, it is difficult to do studies that don't have lots of confounding variables in this area, so when in doubt, use common sense is my rule. We evolved with the sun, so the most likely probability is we have at least some defense to it, and more than likely we evolved so that at least some exposure has benefit.