The utility of heart rate and minute ventilation as predictors of whole-body metabolic rate during occupational simulations involving load carriage

Abstract

The utility of cardiac and ventilatory predictors of metabolic rate derived under temperate and heated laboratory conditions was evaluated during three fire-fighting simulations (70-mm hose drag, Hazmat recovery, bushfire hose drag; N = 16 per simulation). The limits of agreement for cardiac (temperate: − 0.54 to 1.77; heated: − 1.39 to 0.80 l min^− 1) and ventilatory surrogates (temperate: − 0.19 to 1.27; heated: − 0.26 to 1.16 l min^− 1) revealed an over-estimation of oxygen consumption that exceeded the acceptable limits required by occupational physiologists (N = 25; ± 0.24 l min^− 1). Although ventilatory predictions offered superior precision during low-intensity work (P < 0.05), a cardiac prediction was superior during more demanding work (P < 0.05). Deriving those equations under heated conditions failed to improve precision, with the exception of the cardiac surrogate during low-intensity work (P < 0.05). These observations imply that individualised prediction curves are necessary for valid estimations of metabolic demand in the field.

Abstract

Practitioner Summary: Cardiac and ventilatory surrogates are often used to approximate the metabolic demands of work. In this study, however, such predictions demonstrated unsatisfactory agreement with simultaneously measured values across three fire-fighting simulations. Therefore, individually calibrated equations appear necessary to obtain the level of predictive precision required by occupational physiologists.

Keywords:

• fire fighting
• heart rate
• metabolic demand
• oxygen consumption
• ventilation

Disclosure statement

There are no conflicts of interest.

Notes

^1. Email: [email protected]

^2. Email: [email protected]

Additional information

Funding

Sean Notley was supported by an Australian Postgraduate Award (Department of Innovation, Industry, Science and Research, Australia) funded through the Defence Science and Technology Organisation (Melbourne, Australia).