Etude pratique des postes de travail et critique des résultats

Summary

Oxygen consumption and heart rate have been measured by 47 workers of a motor car factory. 20 were also investigated in the laboratory in order to determine on the bicycle ergometer the same parameters at different loads and the individual aerobic power. The advantages of telemetry for the measurement of heart rate are presented. The relationf _h/$\dot V_{O_2 }$ is quite the same at work and on the ergometer. Consequently, it is possible to use the heart rate only to measure the energy expenditure at work by these industrial workers. Is is possible to determine on the ergometer the load equivalent to the industrial work. In this case, the equivalent load is about 75 watts ($\dot V_{O_2 }$ between 800 and 1260 ml/min.). In peak activity, our workers need no more than 55% of their aerobic power and no more than 78% of their maximal heart rate. During a working period of 3 hours, obviously with resting periods, the workers use about 58% of their maximal heart rate and about 24% of their aerobic power. The importance of the percentage of aerobic power and of maximal heart rate used at rest should be taken into account for the interpretation of the results. In our study each worker able to perform 75 watts with a heart rate lesser than 78% of his maximal heart rate and with an oxygen uptake lesser than 55% of his aerobic power should be considered fit for this industrial work. The utilization of the basal heart rate as proposed byHettinger seems us inaccurate and obviously inadequate for rehabilitation of cardiac and pulmonary patients. The study of energy expenditure during occupational work requires further investigations in order to know what percentage of the aerobic power can be allowed during a 8 hours continuous activity in other jobs. The importance of peak works frequency needs further studies.