Body temperatures in relation to heart rate for workers wearing impermeable clothing in a hot environment.

Thermal reactions and heart rate were measured for men wearing impermeable clothing in a hot environment. Even at rest, the Ts increase was remarkable. At the 30th minute, Ts reached 37.2 +/- .4 degrees (+/- SD). Experimental walking (wearing impermeable clothes) occasioned significant (p less than .001) rises in thermal reactions and HR in comparison to control walking; Tr, Tb, Ts at the 30th minute were 38.4, 38.4, 38.1 degree C respectively, and HR was 162 beats/min. No plateau for these responses was reached during 30 minutes of experimental walking. Tr continued to rise after the subjects stopped exercising. The regression equation of Tr on HR in experimental walking differed from that of control walking. If Tr is used as an index for work safety, a lower Tr is needed under such severe conditions.