Rowan Jacobson

you'd be less likely to hurt your knee, but obviously that wouldn't be good overall because we know exercise does a lot of other good things for you.

And starting to look like sun exposure works kind of a similar way where it's almost like exercise for your skin.

I think it's because in the case of exercise, we had a strong sense that it was good for us, you know, right out of the gate.

And we actually, you know, I'm actually going to contradict myself now because I think way back, we all did have a good sense just throughout history that the sun was a positive force.

But then it was only in the 20th century, once we learned about skin cancer, that we suddenly flipped.

And I think part of the problem was that people naturally like to be in the sun.

It actually triggers natural endorphins in the brain, sunlight hitting skin.

um so everyone's naturally drawn to it so when dermatologists and oncologists started telling people don't get sunlight it didn't work very well like people kept going toward the sun even you know even when they're getting the tsk tsk tsk from their doctors so then the messaging got stronger and stronger and stronger and probably left the science behind in an attempt to sort of like brute force people into doing what they wanted them to do

That's an excellent question.

That is a really good question.

And that's a question a lot of scientists are asking right now.

So sunblock, the way it's supposed to work is it blocks the ultraviolet portion of the solar spectrum.

Those are the highest energy photons of light.

from the sun.

And they're the ones, because they have all that energy, they're the ones that can really damage our skin cells and damage DNA and start to trigger that process that leads to cancer.

So those are the ones that get blocked by sunscreen, which lets in the visible light and a tiny bit of the ultraviolet light.

But those ultraviolet wavelengths are also the ones that produce vitamin D in the body.

And now we're learning other compounds like nitric oxide that are looking like they're really important.

So yeah, the sunscreen is going to block the good and the bad.

And so then you start asking questions about the trade-off, like is it more good or bad?