thanks for your answers ...
so even with a good modern sunscreen I might age quicker if I live in these regions ?
even if I take care of reapplying often ?
so even with a good modern sunscreen I might age quicker if I live in these regions ?
even if I take care of reapplying often ?
No. That's the point of a good modern sunscreen. It will protect you. Relax.
The opinion on this issue varies.
There is the common idea that by inducing free radicals and MMPs the sun ages you. Aside from UV radiation, visible light and infrared radiation also induces both of these, it was even found that in some cases 90% of this effect was found in cloth-covered skin - so merely by the infrared radiation of the sun: http://www.ncbi.nlm....act&holding=npg - This is the popular opinion. With popular I don't mean that its more valid.
However, there is also another less popular opinion: MMPs are involved in processes other than degradation of collagen / elastin, and the MMPs responsible for photoaging are induced by neutrophils. These neutrophils are only induced by UV radiation. To see a good position for this view: http://www.nature.co...ymp200915a.html
Now you can take a look at both of these studies and the data yourself and try to find a conclusion. I'm not sure there is enough research to say for sure which it is. Modern sunscreen protects you against UVB and against UVA, maybe not totally perfect at the very end of the UVA spectrum but decent. It does nothing against ir and visible light, antioxidants might help somewhat but also don't offer full protection.
Maybe your sunscreen protects you almost fully against photoaging, maybe not, depends on how you interpret the current research.
Edited by Heyman, 24 September 2014 - 11:15 AM.