You have a base level of resistance determined by your genes. When you get burned you tan and that burn is a function of time spent out in sun multipliednby that base protection. Tanning is our bodies response to the damage done by this as a form of preventing more damage. The damage however is accumulative.

This makes since sense, but still feels too simplified. I used to spend many hours outside and basically developed a skin type that was easily two types higher than I have normally. When this happened, I found I could definitely do longer without a hat or other sun shades with no negative impact.

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.

You repeatedly damaged your skin to maintain the tan.

I get that. But some damage is different from other damage. Getting callouses is similar to getting blisters. But one is much worse for you. (With the other being somewhat beneficial...)

So my question is how bad is it, really? Straw man arguments of folks being ridiculously tanned from tanning beds aside, is there much trustable discussion over mild tans?

Edit: Probably better asked in terms of my blister analogy. Is there benefit to getting tanned similar to building up callouses? Or is it purely cosmetic?

Getting burned once in a two year time span triples your risk of developing melanoma compared to not getting burned at all. That base level obviously depends on your genetics.

That is getting burned. Is tanning:burning the same as callouses:blisters?

I suppose I am assuming callouses aren't really bad for you? Is that not true?

You don't have to be visibly horribly red to be burned. Even just a slight redenning of the skin or it being hot after being in the sun for a while can constitute a burn.

Then let me shift this. If you moved to a location that was completely isolated from the sun, would that cause damage?

That is, I've been assuming there is a spectrum from no exposure to too much. Just as it is with plants. Now, plants obviously need some exposure for photosynthesis. People don't have that, but are there benefits to some base level exposure?

And again, I get the point on burning. And again, that is why I bring up blistering. Something that is obvious in it being bad damage for your skin. Whereas moderate dosing the same behavior could instead give you a callous, which I have never heard called out as bad damage to your skin, though it seems it is a form of damage.

This article seems to say that getting a base tan helps to get 3-4 SPF, so your time-to-sunburn increases up to 4 times. https://www.health.harvard.edu/blog/problem-tanning-myth-bas...

I would not rely on it overall tough.

That was the first thing I wondered too. My skin is Type I or lighter going by the chart. But my neck and arms and face are much darker from a life spend outside. It says I can only go outside for seven minutes without sunscreen, which i believe if i was at the beach, but I know I can go outside much longer than that in a t-shirt without any burn.

You are repeatedly damaging your skin which is why it's darker.

You are repeatedly damaging your muscles and tendons in the gym which is why they become bigger, stronger and denser. So where does that leave us?

How many times have you heard of someone getting muscle cancer from going to the gym?

Are you dumb or just a troll?