ON DIURNAL AND SEASONAL CHANGES IN BODY FUNCTIONS OF LABORERS WORKING IN A HOT ENVIRONMET

Abstract

1. Body functions as revealed by body temperature, pulse rate, blood pressure, body weight and grip strength were observed in two to four days every month throughout a year in a team of seven workers working in a hot environment. Measurements were made six times in a shift, beginning just before the commencement of work and ending just after the finish. 2. In the case of daytime shift, body temperature showed two maxima at about 9.30 a.m. and 3 p.m., pulse rate and blood pressures (systolic and pulse) showed S-shaped change, concave in the morning and convex in the afternoon. In the case of night shift, body temperature, pulse rate, as well as blood pressures showed skew V-shape, lowering in the early morning. In this case, exact phase displacement of body functions by 12 hours could not be seen, although disturbances of the natural physiological wave were detected in body temperature and systolic blood pressure after the midnight. 3. Besides work, rest, food-intake and psychic influences, environmental temperature was found to have difinite effects on physiological manifestations. 4. Monthly changes of physiological functions were relatively closely related to temperature conditions of the working place and those of the room for measurement. Body temperature, pulse rate, or decrease of body weight (apparent as well as net) had a peak in summer and a bottom in winter, while systolic blood pressure or pulse pressure showed just the reverse. In the case of night shift, such differences in body functions in summer as against in winter were not so clear as in the daytime shift.