The physical work rate, the energy and the cardiac costs of twenty seven young male workers from the eastern part of India in five groups handling loads of about 30, 60, 75, 90, and 125 kg, respectively, were ascertained with the objective to rationalize the rate of work based on the physiological responses of the workers. The mean rate of usual work of the groups (I to V) was 4,715, 8,020, 7,350, 6,100, and 7,660 kg(m/min), respectively, which was considered to be extremely heavy. From the mean values of all the groups for the average work pulse rate of 143.1 beats/min, the recovery pulse sum of 119 beats for the first five minutes of recovery, the first and third minute recovery pulses of 127 and 114, respectively, the oxygen pulse of 0.25 ml/pulse/kg, and the energy cost of 9.1 kcal/min, it was suggested that excepting the first group, the workers were working at a level much higher than the 50% level of their maximal working capacity. The simple and multiple linear correlation coefficients between the rate of work and the various physiological parameters were significant and different linear regression equations were suggested. In conclusion, for extremely heavy types of work in India, 1,200 kcal as the net optimal energy output in an 8 hr working day is suggested.