The Physiological Principle of Minimum Work

Abstract

The work required to drive blood through a section of artery and the work (fuel) required to maintain the mere volume of blood in that same section are discussed. Their sum is taken as the total cost of operation of a given section of blood vessel. On this basis, it can be calculated that the cost of upkeep of whole blood is 0.02-0.04 cals. per cc. per day (i.e., of the same order as for tissues in general in the basal state). The blood flow per minute through any vessel (up to a diameter of about 0.32 cm.) is proportional to the cube of its radius. The work of the heart equals 1/2 the work required for upkeep of the arterial blood volume.