Relation of Circulating Red Cell Volume to Body Density and Obesity 1

Abstract

The over-all metabolic activity of adipose tissue in man and other mammals has not been defined as carefully as that of other major organs and tissues. Despite recent reports (1, 2) showing that adipose tissue partakes in many biochemical reactions common to other tissues, widespread opinion holds that fat depots serve little purpose other than storage.A primary index of metabolic activity in any organ is the blood flow through the organ. In this regard, some investigators favor the opinion that blood volume in the adult remains unaltered as body weight increases with fat deposition, and therefore blood volume and body weight correlate poorly in adults and should be well correlated with lean body weight (3, 4).The study reported here was undertaken in order to obtain an estimate of the range of circulating red cell volume in men and women having differing degrees of obesity in an attempt to assess the relative importance of obesity tissue as an "organ" associated with a "fixed " quantity of blood. METHODS

Red Blood Cell Volume, Plasma Volume and Total Blood Volume in Healthy Elderly Men and Women Aged 64 to 100

“…We wanted to determine a nomogram from which to predict the red blood cell, plasma and total blood volumes from body surface area and body weight. Red blood cell, plasma and total blood volumes were found to correlate with both body surface area (BSA) and body weight (BW), a finding similar to that reported by other investigators who studied younger subjects [1][2][3][4][5][6][7][8][9][10] . In our study, the regression equations were slightly more accurate for body surface area (BSA) than for body weight (BW).…”

“…However a study of younger subjects has shown that lean body mass correlated with red blood cell volume 3 and with red blood cell, plasma and total blood volumes 7 .…”

Red Cell, Plasma, and Blood Volume in Healthy Women Measured by Radiochromium Cell-Labeling and Hematocrit*

“…Data for both sexes fell on the same linear regression line relating blood volume, in milliliters per kilogram, to total body density in the study of Allen and coworkers (10). Huff and Feller's findings (13) for whole blood were similar, although at any given body density women tended to have lower cell volumes and higher plasma volumes in milliliters per kilogram than men. The latter suggests that sex-associated factors other than body density or fat content may influence the Vrbc andl relative cell volume.…”

“…The lower content of hemoglobin (11,12), red cells (13,14), and blood (10,(15)(16)(17) per unit of bo)ly size in women than in men is usually attributed to the higher fat content of the female. It has been reported that the difference between the sexes becomes insignificant when Vrbc is related to lean body mass calculated from body water (14) or when blood volume is related to total body water (15).…”

RED CELL, PLASMA AND BLOOD VOLUME IN HEALTHY MEN MEASURED BY RADIOCHROMIUM (Cr51) CELL TAGGING AND HEMATOCRIT: INFLUENCE OF AGE, SOMATOTYPE AND HABITS OF PHYSICAL ACTIVITY ON THE VARIANCE AFTER REGRESSION OF VOLUMES TO HEIGHT AND WEIGHT COMBINED*

“…Some of this variation presumably results from differences in body composition, since blood volume correlates both with body density (5,15) and with lean body mass (16,17). However, it has not been shown that predictions based on total body mass are less accurate than those based on lean body mass, which requires a separate measurement (15,16). Consideration of fat thickness and girth measurement, in addition to height and weight, was found by Hicks, Hope, Turnbull and Verel to improve prediction (14).…”