Hands turning white while sprinting. No blood? page

[Knifegill]

What could this mean? Is my body channeling blood to my vitals in expectation of potential injury to a limb? Why does my body do this?

[jfreaksho]

Or perhaps to your legs, where it is being used.

The blood vessels in my arms get huge and swollen and stick out when I'm doing arm work, especially when my arms are lower than my heart, like with pushups. I've never checked to see what is happening to my feet at that time, though.