The main cause of intermittent claudication is a condition called peripheral artery disease (PAD). That condition happens with atherosclerosis, which is a buildup of a wax-like substance called plaque on the inside of your arteries. As that buildup gets worse, there’s less room for blood to flow through those arteries. PAD happens when plaque buildup causes significant or severe narrowing of the arteries that feed your limbs (especially your legs). Much like a closed lane on a road causes traffic to slow down and back up, narrowing of your blood vessels slows down blood flow to your limbs