A further investigation of the net heart rate method to estimate the oxygen cost of occupational physical activity

The oxygen consumption and heart rate response of nine subjects was measured in the laboratory during five minute bouts over five activities. Prediction equations using the method of least squares were developed to estimate oxygen consumption from heart rate using six different approaches and three relationships. The total oxygen consumption for the full twenty five minutes of activity was calculated using three different calculation methods and the results compared to the measured volume over the same period. In addition a field study was undertaken over three days during which the subject's heart rate response to a full day's work shift was recorded. On one of these days each subject's physical activities was observed, recorded and coded by the researcher. The field study demonstrated that heart rate responses in the field were consistent with those obtedned in the laboratory. It also demonstrated that estimates of energy expenditure rates calculated from the prediction equations yielded results consistent with those in the published literature.