Ventilatory threshold (VT) is an important index of aerobic exercise function. The non-invasive nature of assessing VT and the fact that VT can be determined without obtaining a maximal exertion makes it broadly appealing to study in both healthy and diseased populations. Much of the understanding of the physiological and biochemical events underlying the occurrence and significance of VT is based on research involving adults. Several conclusions can be made from the studies which have examined VT in children. First, VT can be determined in a reliable manner. Second, heart rate deflection has been used as an alternative method to estimate VT and, based on limited information, appears to have reasonable accuracy. Third, although there is some evidence suggesting that VT (relative to maximal oxygen uptake [V̇O2max]) declines with maturation, the evidence is not overwhelming and it is based primarily on cross-sectional comparisons. Fourth, endurance training will increase VT in children to a greater extent than the increase in V̇O2max. Lastly, the physiological significance of VT and the metabolic consequences when exercise intensities exceeds VT are not well understood in children and are fruitful areas of research.
The authors are with the Human Performance Laboratory at Ball State University, Muncie, IN 47306.