10
votes
2answers
181 views

Why does sunscreen not work all day?

All over the internet it says that sunscreen does not work all day, but does not say anything about why. Why does sunscreen not work all day? Does the matrials get destroyed by the UV rays? Or is it ...
4
votes
1answer
84 views

What is SPF in sunscreen cream?

What is SPF in sunscreen creams? I go to 2500m-4000m altitude. What should I use? And I've heard that SPF more than 55 is not for men. Does more SPF mean more sun protection? What would be an ...
1
vote
3answers
156 views

Sunblock for clothing-optional camping

What should I look for in a suntan lotion for a nude camping trip? I don't know what to look for when it goes on the whole body. Are there any ingredients that I should watch out for?
10
votes
1answer
121 views

Is there simple guidance on sunburn risk associated with altitude?

When skiing, if the weather is good, I often come back with a better tan than if I have been at the beach. Obviously with altitude, there is less blocking of UV rays by the atmosphere. But how much ...
14
votes
2answers
1k views

How harmful is the rising/setting sun?

Often, while hiking, my companions and I treat the very early/late sun as being less harmful (as far as skin cancer and UV radiation are concerned). For example, we might not apply sunscreen ...