The purpose of this study is to estimate the work loadintensity and the energy consumptionrate during farm work by means of observingthe heart rate. Analysis of the heart rate was done usingseveral work modelsand the results indicated are as follows :

(1) The heart rates before and after the working periodwere different from each other. As such, the base heart rates used hadto be calculated based on these deviations.

(2) The coefficient of variation of heart rates is inverselyproportional to the work load.

(3) The pattern of the percent increase in heart rateis better than the pattern of the heart rate itself, in terms of correlationwith the oxygen consumption rate, energy consumption rate, increase inenergy consumption and R.M.R..

(4) The strongest correlation (r=0.974) occurred betweenthe percent increase in heart rate and the increase in energy consumptionduring the last 4-6 minutes of the work period.

(5) The percent increase in heart rate could be used toestimate the energy consumption and/or any corresponding increase in energyconsumption due to increase in load.

(6) It was observed that a coefficient of variation of3% for the heart rate generally indicates the point from which job overloadoccurs.