If pulse pressure is so important in predicting risk, we need to consider other determinants of blood pressure in general and of pulse pressure in particular. An individual's blood pressure is determined both by cardiac output, a product of stroke volume and pulse rate, and by peripheral resistance. Peripheral resistance may be structural - resulting from vascular wall thickening, or functional - resulting from resistance vessel constriction. However, in addition to these long recognised components of blood pressure determination, there is also the influence of conduit vessel elasticity. The importance of this will be emphasised later.