Circulatory Studies in Well Trained Athletes at Rest and During Heavy Exercise, with Special Reference to Stroke Volume and the Influence of Body Position

Abstract

Eight well trained athletes (cyclists) with large dimensions of the circulatory system were studied with heart catheterization at rest and during exercise at 800 and 1,600 kpm/min both while sitting and supine. The results are compared with data from non‐athletes. The cardiac output at rest and during work showed the same relation to the oxygen uptake as in nonathletes. The cardiac output was less in the sitting than in the supine position by 2.6 1/min at rest and 1.8 1/min during heavy work, due to a smaller stroke volume in the sitting position in both groups. On transition from rest to exercise the stroke volume increased 9 % in the supine and 48 % in the sitting position. After these initial changes the stroke volume remained constant during continued exercise with the heavier load in both body positions. The difference in stroke volume between supine and sitting position averaged 43 ml at rest and 9 ml during heavy exercise. The stroke volume during work in the supine position showed the same relation to the blood volume as in the nonathletes. The stroke volume was larger than expected from the size of the heart, when compared with the previously demonstrated relationship in nonathletes. The rate of work, performed at pulse rate 170, bore approximately the same relationship to the stroke volume during exercise in both groups. The larger oxygen transport capacity of these athletes as compared to nonathletes is explained by a larger stroke volume. During exercise the ventricular filling pressures were higher than in nonathletes.

Left ventricular performance in normal subjects: a comparison of the responses to exercise in the upright and supine positions.

“…Hemodynamic studies have generally, but not unanimously, shown that stroke volume increases with transition from rest to exercise in both the upright and supine positions. ", 4,[8][9][10][40][41][42] LV end-diastolic volume during supine exercise has been shown to decrease in studies in which metallic epicardial markers" and angiography were used.14 Using angiography, Gorlin et al12 found no substantial change in LV enddiastolic volume. Crawford et al6 demonstrated echocardiographically that diastolic diameter does not change during moderate supine and upright bicycle exercise.…”

Cardiac Effects of Exercise Training in Hypertension

“…Chronic exercise training has been shown to enhance myocardial diastolic function [55][56][57], alters calcium uptake in the SR [57], and induces sinus bradycardia [53]. Interestingly, exercise conditioning may potentially reverse diastolic dysfunction-associated pathologic hypertrophy [58] and/or with minimal effects on ischemia/reperfusion injury [59] while also lessening ageassociated declines in diastolic function [54].…”

“…Chronic exercise training causes a bene�cial adaptive response of the cardiovascular system, that is, decreased resting and submaximal heart rates and increased LV �lling time, venous return, and stroke volume [53,54]. Chronic exercise training has been shown to enhance myocardial diastolic function [55][56][57], alters calcium uptake in the SR [57], and induces sinus bradycardia [53].…”

Cardiopulmonary Responses at Various Angles of Cycle Backrest Inclination.

“…position [2][3][4][5][6][7][8] . In general, the AT and peak VO2, which are determined from cardiopulmonary exercise testing, were lower in the supine position than in the upright position 5)8) .…”

“…Many researchers have reported comparisons of cardiopulmonary responses during upright and recumbent (supine) exercises [2][3][4][5][6][7][8] . Generally, it has been reported that work performance in incremental exercise is enhanced in the upright position as .…”