Revisiting ventilatory and cardiovascular predictions of whole-body metabolic rate.

Abstract

The influence of variations in exercise mode, thermal state, and load carriage on cardiac and ventilatory predictors of metabolic rate were investigated. Fifteen males were studied at rest and during whole-, upper-, and lower-body exercise (unloaded and loaded) under thermoneutral and hot conditions. Ventilatory predictions were superior in thermoneutral (residual mean square error range: 0.04 to 0.17 L·min(-1) vs 0.21 to 0.36 L·min(-1)) and hot conditions (0.03 to 0.07 L·min(-1) vs 0.21 to 0.24 L·min(-1)). Predictions derived from whole- or lower-body exercise, and unloaded or loaded exercise could be interchanged without significant error. Nevertheless, a mode-specific prediction was required for upper-body work, and mild hyperthermia significantly reduced the precision of cardiac predictions. Ventilatory predictions were more precise, but errors from heart-rate predictions could be minimized by using thermal-state and exercise mode-specific predictions.