Body fluid measurements were performed in groups of trackmen, wrestlers, and non-athletes at the University of Pittsburgh. Plasma and blood volumes were determined with an Evan's blue dye-hematocrit method. Total body water and extracellular fluid volume were measured with tritium and 35-sulfate. Radioactivity was determined by liquid scintillation spectrometry using a double-labeling technique. Height, weight and skinfold values were also obtained.
The athletes did not differ from the non-athletes in age, height, or weight, nor did the trackmen differ from the wrestlers in these same characteristics. The skinfold measurements suggested that the athletes were leaner than the non-athletes, and that the trackmen were leaner than the wrestlers.
There was no difference in plasma or blood volumes between any of the groups, The athletes had higher extracellular fluid volumes and total body water than the non-athletes, but the trackmen did not differ from the wrestlers in these same parameters. In all three groups the ratio of extracellular water to total body water was similar.