Veins
 

Has anyone else noticed that people who are regularly physically active seem to have more prominent veins especially in their forearms and hands? Why is this?

I think part of it is the substantial less fatty tissue allowing the vascularity to show. Even though I was a bodybuilder for years, I never had vascularity in my quads as I do now. Also, even though my arms are much smaller, both my forearms and upper arms have substantial vascularity now. I have 5.0% body fat, and the veins just show through when not covered by fat. Also, some people have thinner skin, and show vascularity more readily.

it's genetics and body fat. the lower the fat, the less covers the skin so the mosre you can see. also the lower water retention you have (which is usually where the thick or thin skin comes from) that will also make the veins more visible. Some people just don't have veins that are very prominent because of their genes.

I'll throw in that one could get prominent surface veins due to insufficient or occluded deep veins.

Sorry but I had to :)

I think it might also be due to the fact that your muscles require more blood when you become more active...in order to get more blood to where it is needed, your veins etc expand a little to allow more blood flow and more capillaries form (cant see those though).

Aye, and veins aren't very elastic over time: they generally get bigger, but don't shrink back down again. Add that to low fat, and you've got the reason older athletes have forearms like a bunch of old cables.

hmm. I understood that veins were pretty elastic - serving the function of capitance...

Short-term yes, what I meant (and was perhaps vague about) was that once you've "trained" veins big, they don't get small again half as fast. but I'm talking about lifetime change, not transient pump.