Why if arms and legs are exposed to the sun for the same amount of time, do arms typically come out more tan/burnt?


I thought maybe because the arms have less surface area than the legs but my arms always tan faster than my legs.

In: Biology

The sun is above you. The first thing it hits is the arms. Your body and clothes provide an intermittent shield of shade to your legs. If you were to, say, sunbathe by laying on a lounge chair and don’t move, your legs will tan equally as fast. In some cases, even faster than your arms since the arms have more sunburn preventing melatonin in them from more normal exposure.

Basically put the skin on the legs doesn’t produce the same amount of melanin (the pigment in your eyes, hair and skin) as the skin on your arms and this results in legs getting less tan.

More over, if you’ve got hairy legs then you’re effectively blocking the UVA required to darken the skin. UVA is a type or radiation released by the sun that triggers certain cells beneath the skin and causes it to release more melanin.