Validation and adjustment of the mathematical prediction model for human rectal temperature responses to outdoor environmental conditions

• Published in: Ergonomics 1995-05, Vol.38 (5), p.1011-1018
• Main Authors: Moran, D., Shapiro, Y., Epstein, Y., Burstein, R., Stroschein, L., Pandolf, K. B.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Anatomy & physiology; Biological and medical sciences; Body Temperature; Environment; Ergonomics; Exercise; Fundamental and applied biological sciences. Psychology; Heat load; Humans; Male; Mathematical models; Models, Theoretical; Predictive Value of Tests; Rectal temperature; Rectum - physiology; Reproducibility of Results; Temperature; Thermoregulation; Thermoregulation. Hibernation. Estivation. Ecophysiology and environmental effects; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0014-0139; 1366-5847
• DOI: 10.1080/00140139508925167

Models to predict rectal temperature (T re ) have been based on indoor laboratory studies. The present study was conducted to validate and adjust a previously suggested model for outdoor environmental conditions. Four groups of young male volunteers were exposed to three different climatic conditions (30°C, 65% rh; 31°C, 41% rh; 40°C, 20% rh). They were tested both in shaded and open field areas (radiation: 80 and 900 W-m −2 , respectively) at different work loads (100, 300 and 450 watt). Exercise consisted of two bouts of 10 minutes rest and 50 minutes walking on a treadmill, at a constant speed (1.4m * s −1 ) and different grades. The subjects were tested wearing cotton fatigues and protective garments. Their T re and heart rate were monitored every 5 min and skin temperature every 15 min, oxygen uptake was measured towards the end of each bout of exercise; concomitantly, ambient temperature, relative humidity and solar load were monitored. We concluded that: (a) the corrected model to predict rectal temperature overestimates the actual measurements when applied outdoors; ( b) radiative and convective heat exchanges should be considered separately when using the model outdoors; ( c) radiative heat exchange should also be considered separately for short-wave radiation (solar radiation) and long-wave emission from the body to the atmosphere. Finally, an adjusted model to be used outdoors was suggested.