The following risk factors are associated with CHD: smoking, blood pressure, diet, exercise, genetic influences. Smoking systemically affects the whole cardiovascular system, some unfavourable effects include; impaired oxygen delivery to tissues, increased blood pressure, increased likelihood of blood clotting and a disruption to the healthy cholesterol balance. High blood pressure puts damaging pressures upon the walls of blood vessels, which increases the risk of vascular disease such as blood clotting and aneurysms. Diet and exercise are closely linked, and poor management of either can lead to; high blood pressure, high cholesterol and increase the risk of blood clotting and atherosclerosis. Genetic influences can predispose high blood pressure and blood clotting.