Relationships of oxygen consumption, ventilation and cardiac frequency to body weight during standardized submaximal exercise in normal subjects.

In normal males during submaximal exercise at a constant rate of external work on a bicycle ergometor or step test, the oxygen uptake and ventilation are linear functions of body weight. In normal females the mean oxygen uptakes do not differ materially from those for males of comparable weight. However, because of the constant terms in the regression equations, the convention of expressing results per kg body weight or m2 body surface area may give rise to error; for ventilation this may be avoided by the use of the regression on oxygen uptake. Alternatively, the results may be reported at a constant oxygen uptake, for example, for men 1·5 1/min as recommended by J.L.O. and for women 10·l/min; the ventilation is then independent of body weight. By this procedure allowance is also made for differences in oxygen uptake duo to the effects of practise. For the cardiac frequency a similar adjustment to a constant oxygen uptake yields values which are negatively correlated with body weight for walking on a tre...