Vascularity

Vascularity, in bodybuilding, is the condition of having many highly visible, prominent, and often extensively-ramified superficial veins.

[1] The skin appears "thin"—sometimes virtually transparent—due to an extreme reduction of subcutaneous fat, allowing for maximum muscle definition.

[citation needed] Vascularity is enhanced by extremely low body fat (usually below 10%) and low retained water, as well as the muscle engorgement ("pump") and venous distension accentuated by the vigorous flexing and potentially hazardous Valsalva effect which characterize competitive posing.

[citation needed] Bodybuilders or athletes sometimes dehydrate themselves a few days before a competition or show to achieve this so-called "ripped," vascular look.

Self-dehydration is not recommended by medical professionals, as the negative and sometimes-fatal effects of the resultant water-electrolyte imbalances are well documented.