Abstract
A questien has arisen as to whether or not workers can maintain their health and working efficiency for a long period of time in the case when a specific working system with 3 days cycle comprising of 24 hours work on the 1st day, total rest on the 2nd day and ordinary working hours on the 3rd day is adopted. To answer this question, hourly and daily changes in various physical and mental functions of the workers of a machine factory adopting such working syetem were traced. Roughly the following results were thus obtained.
1. Ordinarily, all night work caused lowering of various physical and mental functions and increase in the fatigue observed from the nutritional phases. In addition, their disease resisting function was usually lowered.
2. Among those various functions seen in the case when this kind of working systemm was adopted, such one as the specific gravity of blood plasma, which demonstrated a kind of habituation and adaptation phenomenon during the latter half of a week was noted. However, most of the fatigue reactions, for example, threshold value of the patellar reflex, Vakat's iodic acid index and mucoprotein discharge, were found clearly increased during the latter half of a week. Moreover, the lowering of the nutritional condition particularly the progress of anemia which was indicated by the daily changes of the hematocrit value, was found to be a matter worth while for a careful consideration in the case when the above working system was continued for a long period of time, though the condition was mild and its major part would be recovered by the rest on Sundays.
3. The fact that, in spite of a remarkable influence of the all night work on the physical and mental functions, any extreme accumulation of fatigue was not noted was presumed to be due to the remarkable effect of the complete rest on the following one day to the recovery from fatigue. Consequently, in the cases where the one day rest was not effectively spent, long term continuation of such working system was considered impossible.
