Renal Hemodynamics, Sodium and Water Excretion in Supine Exercising Normal and Cardiac Patients 1

Abstract

Diminished sodium excretion is one of the factors underlying edema formation in congestive heart failure. The clinical improvement and disappearance of the edema in some cardiac patients treated with bed rest alone suggests the importance of exercise as a potentiating factor in the sodium retention. Exercise studies carried out in normal and cardiac patients in the upright position by other investigators are open to question since the upright position itself is a factor in diminished sodium excretion. In order to exclude postural effects completely, it became necessary to study renal hemodynamics and electrolyte and water excretion in supine exercising subjects.The present study reports the effect of exercise in the supine subject on renal plasma flow, glomerular filtration rate, sodium and water excretion. Fifteen control subjects and eleven cardiac patients were studied. The control series consisted of convalescent patients who presented no evidence of cardiovascular or renal disease. All of the cardiac subjects were receiving digitalis preparations. All had received mercurial diuretics, varying from one day to two weeks prior to the study. The cardiac subjects were divided into two groups depending on their clinical appraisal at the time of the study. In the "compensated" group were placed those patients who were ambulatory, able to lie flat and were free of edema. In the "severe" group were placed those patients who were confined to bed because of limited exercise tolerance. This group required more frequent mercurial diuretics and were orthopneic. With one exception, they were edematous at time of the study.

Exercise and Heart Disease

“…The mean calculated renal blood flow during moderate exercise was 20% of the normal resting value. These figures are in remarkable agreement with renal blood flow measurements during exercise in patients with heart disease by other workers using renal clearance techniques (Aas and Blegan, 1949;Freeman et al, 1955;Judson et al, 1955;Werkd et al, 1954). The only important advantage of our technique is that it allows immediate changes of flow to be studied in a manner not possible with the renal clearance methods.…”

“…persons, but that it is to a lesser degree for a given exertion than in patients with severe heart disease (Freeman et al, 1955) and presumably restricted cardiac outputs. Brain The next regional circulation to be studied during leg exercise was that of the brain .…”

The effect of moderate exercise on the regional distribution of blood flow in the rat

“…Bucht et al (1953) found no change in renal blood flow during light exercise in the supine position, but it decreased during very heavy exercise. Freeman et al ( 1955) found that the bladder clearance of PPaH was unchanged during very severe excrcise of short duration in the supine position. In the above four experimei~ts renal blood flow was measured with the subject in the supine position and did not decrease during exercise.…”

Exercise and Heart Disease

“…persons, but that it is to a lesser degree for a given exertion than in patients with severe heart disease (Freeman et al, 1955) and presumably restricted cardiac outputs.…”