Blood flows around your body as part of the circulatory system. Our bodies were designed to be active and so when you walk your leg muscles actively contract and relax, to pump the blood up through the legs and back to the heart. Healthy leg circulation is where blood carries carbon dioxide and waste products pumped from your legs through your veins back to the heart and oxygenated blood is returned to the legs.
Unfortunately if you have a sedentary lifestyle, the leg muscle pumps are less active and blood flow is reduced. This can cause blood and fluid to pool in the legs and may cause swelling and discomfort otherwise referred to as 'Poor Circulation'.