Is the chronotropic index applicable to children and adolescents?

Background: The aim of the present study was to investigate whether the chronotropic index (CRI) is independent of age, sex, stage of exercise testing, functional capacity and resting heart rate in children, as it is in adult populations.

Methods And Results: A total of 129 normal children and adolescents underwent maximal treadmill exercise testing according to the Bruce protocol. Submaximal chronotropic response was assessed by the CRI at the end of stages 1, 2, 3, and 4 of Bruce treadmill exercise testing.

Simple exponential regression model to describe the relation between minute ventilation and oxygen uptake during incremental exercise.

The physiological significance of an exponential regression model between minute ventilation (VE) and oxygen uptake (VO2) during incremental exercise was examined. Thirty-eight subjects, including 12 patients with chronic heart failure, participated in cardiopulmonary exercise testing on a bicycle ergometer. The equation VE = a e(bVO2), where a and b are parameters, was used to describe the relation between VE and VO2 during incremental exercise.