NIOSHTIC-2 Publications Search
Heat stress tolerance testing.
NIOSH 1980 Dec; :46-60
Two physiological tests for the prediction of individual tolerance to heat were developed. The first test involved a 15 minute period of exercise at room temperature, at a load of 80 watts. Following the recording of heart rate and rectal temperature at the end of the 15 minute exercise period, a composite score was compiled to predict heat tolerance. Individuals who were heat intolerant presented high heart rates and rectal temperatures upon the completion of the exercise in the temperate environment, the corresponding responses reflect the poor condition of their cardiovascular and thermoregulatory systems. The second test, which was developed primarily for use in industrial situations and as a preemployment test to predict heat tolerance, involved a 10 minute exercise test at a predetermined work load, heat stress and clothing. Heart rate values were recorded at 5 and 10 minutes of exercise and the respective differences were used to predict tolerance time. The results of studies based on 18 different combinations of work loads, clothing, heat stress levels and acclimatization conditions yielded tolerance times ranging from 30 minutes to 3.2 hours. The plotting of the heart rates recorded at 5 and 10 minutes of exposure against tolerance time yielded a power curve for the prediction of tolerance time. The authors conclude that a 10 minute exposure to standard heat stress conditions can be used to predict heat tolerance.
Thermal-effects; Physical-exercise; Physiological-measurements; Body-temperature; Hemodynamics; Heat-regulation; Metabolic-equilibrium
DHHS (NIOSH) Publication No. 81-108
Proceedings of a NIOSH Workshop on Recommended Heat Stress Standards, September 17-19, 1979, Cincinnati, Ohio
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division