“…In contrast, Bass, Buskirk, Jampietro and Mager (22) found no increase in Vpl or Vrbc after three weeks of vigorous physical conditioning and Buskirk (23) was unable to demonstrate differences in Vpl or Vwb per unit of total or fat-free body weight in moderately or rigorously trained athletes and nonathletes. The demonstration by Kjellberg, Rudhe and Sjdstrand (21) of large differences between the blood volumes of athletically trained and untrained persons requires re-examination. The carbon monoxide method which they used is particularly unsuitable for this problem, since 15 per cent of the test dose of gas leaves the blood during the measurement and goes mostly to muscle pigments (25,27 2.…”