Claudication 

Claudication is a symptom of peripheral vascular disease, which is also known as peripheral arterial disease.  Claudication is pain and/or cramping in the lower leg due to inadequate blood flow to the muscles. The pain usually causes the person to limp. Claudication typically is felt while walking, and subsides with rest. It is commonly referred to as "intermittent" claudication because it comes and goes with exertion and rest. (In severe cases, the pain is also felt at rest.)

The usually intermittent nature of the pain of claudication is due to a temporary inadequate supply of oxygen to the muscles of the leg. The poor oxygen supply is a result of narrowing of the arteries that supply the leg with blood.

Causes

The most common cause of peripheral vascular disease(PVD) is atherosclerosis (hardening of the arteries).  Atherosclerosis is a gradual process in which cholesterol and scar tissue build up to form a substance called plaque that clogs the inside of the artery. This build up causes a gradual narrowing of the artery, which will decrease the amount of blood flow. This limits the supply of oxygen to the leg muscles and is especially noticeable when the oxygen requirement of these muscles rises.