The Amount of Hemoglobin (Blood Volume) in Relation to the Pulse Rate and Heart Volume During Work

Summary. By determination of the total amount of hemoglobin and the blood volume estimated on that basis, in a material of children, women and men, including athletes a very marked correlation, + 0.82 and + 0.90, respectively, was found between the amount of hemoglobin and the pulse rate during work—or the work at which the pulse reaches a level of about 170 beats per minute. This indicates that there is a close correlation between the total blood volume and the stroke volume during work. In 12 persons (among the adults) with different amounts of hemoglobin, the heart volume was determined during the performance of a varying amount of work on the bicycle ergometer. In one group of the tested persons the heart volume diminished only slightly up to a pulse rate of about 150 beats per minute, but afterwards more rapidly. In another group the heart volume diminished in proportion to the increase of the pulse rate. The first‐mentioned group consisted of individuals of average build, the latter of men of more leptosomatic type, with a small amount of hemoglobin in comparison to body height. When the movements of the left ventricular and of the aortic walls were recorded during the different cardiac periods with electrokymography, it was found that the systolic emptying of the left ventricle greatly increased during work, although the heart volume remained unchanged or was actually less than during rest. It was also shown with the same technique that there was a parallelism between the change in the heart volume during work and the filling of the left ventricle. There seems to be no direct correlation between the heart volume and the stroke volume in the same individual, an assumption, which might be expected if the stroke volume were regulated in accordance with Starling's heart law. These findings are discussed and a new hypothesis in regard to the regulation of the blood circulation and the blood distribution is advanced in order to explain the results found in normal man.