Theoretical principle of the indirect method for cardiac output determination by continuous gas-analysis of prolonged expiration was introduced and its practical utility and error sources were discussed.
Merits and demerits of this method are as followd;
1) No blood sampling nor catheterzation is required.
2) Nonphysiological gas inhalation or injection of dye or other substances are not required.
3) Real time determination of cardiac output is possible when used with online computor processing.
4) Repeated measurement on the same subject is able to perform once every two minute at rest and once a minute during exercise.
5) Measurement during exercise is performed without any dificulty.
6) Several suppositions which used in this method may cause some error, especially anemia and unevenness of ventilation-perfusion ratio are possible two major error sources.
Using a gas-spectometer, cardiac output of six subjects was measured by this principle at rest and during exercise of several intensities on a bicycle ergometer. Average values of cardiac output were 4.5, 7.5, 9.4, 12.3, and 14.1 1/min. at rest and during exercise of 150, 300, 450, and 600 kpm/min., respectively.
From the results, utility of this method was practically confirmed for application to exercise physiology.

Effects of long term physical training on body composition and physical fitness were studied on 110 healthy males aged between 28 and 34 years. Two and a half hours training of soccer, swimming, running, judo and other kinds of exercises were assighned to the subjects daily except sunday for 8 months. Body weight, overweight, body fat, skinfold thickness, blood pressure, vital capacity, body flexibility, power, grip strength, maximal work capacity, and 6 kinds of sport tests were compared before and after the training.
1) Energy cost of the daily exercise was estimated at about 950 Cal., and intensity of the exercise was deduced to be 4 in RMR (corresponds to about 5 in Nets) on the average.
2) Body weight did not change significantly on the average. However, obese subjects lost their weight, lean subjects gained, and normal weighted subjects did not change their weight significantly.
3) Body fat calculated from skinfold thickness decreased markedly, and the more fat the subjects had initially, the more fat they lost.
4) LBM increased in almost all cases. Obese subjects lost more fat than LBM they gained, and lean subjects gained more LBM than fat they lost. Normally figured subjects gained the same weight of LBM as the fat they lost.
5) Physical figure tended to converge by the training into some range in which the relationship between body weight and height is 4-5% more stout than that of average Japanese male adults.
6) Overweight calculated from weight and height may be used as a valid indicator of obesity for untrained people but not for well trained. While body fat can be a good indicator of that for the both groups.
7) Body fat of the subjects who had high work capacity was mostly under 13%, and that of the subjects whose work capacity was poor was mostly over 13%, while, that of the subjects whose work capacity was medium scattered in the both sides of 13%.
8) Performance of both aerobic and anaerobic exercise improved markedly by the training.