Abstract
On the basis of the close relationship between oxygen intake and heart rate or pulmonary ventilation, the estimation of oxygen intake from heart rate or pulmonary ventilation has been proposed for use in field studies from the viewpoint of avoiding the cost and complexity of gas analysis. Some authors have pointed out that pulmonary ventilation has an advantage over heart rate since instead of the construction of separate regression lines for each subject an over-all regression for at least homogeneous groups of subjects would result only in a small loss of accuracy. In a previous paper the authors presented an equation estimating oxygen intake from heart rate. However this equation is available for male subjects. The purpose of this study is to make the equation for females and to investigate its reliability, and to compare it with the prediction from pulmonary ventilation.
During six kinds of ergometer work of 150 to 600kgm/min, the oxygen intake, pulmonary ventilation, and heart rate were measured on four young adult females. For the whole subjects and for each individual, different regression equations of oxygen intake on pulmonary ventilation or on heart rate were calculated. In addition, from the data about different 13 female adults measured previously in our laboratory, a different regression equation of oxygen intake on pulmonary ventilation were obtained for the whole 13 subjects and a new equation for prediction of oxygen intake from heart rate was proposed as Vo2= vo2(0.558HR-28.5)/(0.558hr-28.5) where Vo2 is estimated value of oxygen intake during the work under investigation corresponding to vo2 (oxygen intake during a given submaximal test work), hr (heart rate during the test work), and HR (heart rate during the work under investigation). This new equation was made to be used for adult females, on the basis of indirect determination of maximal oxygen intake and heart rate during a submaximal work.
Estimated values of oxygen intake during the six kinds of ergometer work were computed using the above different regression equations, the new prediction equations, and the prediction equations proposed by SARTORELLI (1950), FORD & HELLERSTEIN (1959), and RAMANATHAN (1964). Although the best prediction was obtained in the case where the individual regressionsof oxygen intake on heart rate were applied to the same individuals, considerably high reliability of the new prediction equation which the present authors proposed here on the basis of our previous results in our laboratory were confirmed. The reasons why the new equation could make the high reliability in the prediction of oxygen intake were discussed from the viewpoints of sex difference and individual difference in the regression of oxygen intake on heart rate or on pulmonary ventilation, and a small individual difference in the regression of % Vo2 max on heart rate was regarded as the main reason for the advantage of the new prediction equation over the other over-all regressions and prediction equations tested here.
