Objective: The influence of variations in exercise mode, thermal state, and load carriage on cardiac and ventilatory predictors of metabolic rate were investigated.
Methods: Fifteen males were studied at rest and during whole-, upper-, and lower-body exercise (unloaded and loaded) under thermoneutral and hot conditions.
Results: 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.
Conclusion: Ventilatory predictions were more precise, but errors from heart-rate predictions could be minimized by using thermal-state and exercise mode-specific predictions.