this is strange, but I have the feeling I have to apply more sunscreen to my arms and shoulders. OTOH I feel my legs and torso don’t need as much stuff, neither does my face.

When I sunbath I only wear my swim trunks and I lay on the ground, which means my legs and torso receive the same amount of radiation as my arms and shoulders.

I could understand that my arms and shoulders needed more sunscreen if I walked under the sun, but that’s rarely the case: I lay on the ground.

Does this happen to you?

my arms are thinner than my legs: do I need more sunscreen in the areas where blood vessels are thinner / muscles are leaner?