Validation of Physiological Strain Index Based on Heart Rate in Experimental Hot Conditions

Ayoub Ghanbary Sartang, Habibollah Dehghan


Heat stress is a common problem in industrial workplaces. Thermal stress is a caused reduces concentration of and fatigue increases individuals and thermal condition can be one of accident risk factors .The purpose of this study was validation of Physiological Strain Index Based on Heart Rate in experimental condition.
This Semi experimental study was conducted to 16 male in five different temperature conditions (21, 24,27,30,35ºC) in the climate chamber and on the treadmill with two levels of activity 2.4 kph (light physical activity) and 4.8 kph (medium physical activity).Heart rate was measured to for calculating Physiological Strain Index Based on Heart Rate, rate perceived exertion and questionnaire Heat Strain Score index was measured. The correlations between the indices were evaluated using Pearson correlation test and regression analysis.
Pearson correlation test showed a significant correlation between Physiological Strain Index Based on Heart Rate and rate perceived exertion (p≤0.001,r=0.96).also a high correlation was observed between Physiological Strain Index Based on Heart Rate and wet bulb globe temperature (p≤0.001,r=0.90). A very high correlation was observed between Physiological Strain Index Based on Heart Rate and Heat Strain Score Index (p≤0.001, r=0.93).
The results of this study showed Physiological Strain Index Based on Heart Rate a suitable method for strain heart evaluation is caused by thermal stress because there was an acceptable correlation with heat stress valid indices.


Physiological Strain Based on Heart Rate, Heart Rate, heat Strain, perceived exertion, climate chamber

Full Text:



Golmohammadi R, Aliabadi Mohsen. Air Conditioning control in Workplace, Journal of Hamedan University of medical science.; 2012;1(1):124 - 70. (Persian).

Jafari MJ, Hoorfarasat G, Salehpour S, Khodakarim S, Haydarnezhad N. Comparison of Correlation between Wet Bulb Globe Temperature, Physiological Strain Index and Physiological Strain Index Based on Heart Rate with Heart Rate and Tympanic Temperature on Workers in a Glass Factorye. 2014;2(1):55-64.

Ayyappan R, Sankar S, Rajkumar P, Balakrishnan K. Work-related heat stress concerns in automotive industries: a case study from Chennai, India. Global Health Action. 2009;2(1):27-38

Moran DS, Shitzer A, Pandolf KB. A physiological strain index to evaluate heat stress. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 1998;275(1): 129-34.

Gleim GW, Nicholas JA. Metabolic costs and heart rate responses to treadmill walking in water at different depths and temperatures. The American journal of sports medicine. 1989;17(2):248-52.

Dehghan H, Habibi E, khodarahmi B , Yousefi H, Hasanzadeh A. A Survey of the Relationship of Heat Strain Scoring Index and Wet Bulb Globe Temperature Index with Physiological Strain Index among Men in Hot Work Environments. Journal of Health System Research. 2012;7(6): 15-24. (persian).

Borg G. Borg's perceived exertion and pain scales: Human kinetics; 1998;3(1):278-280

Tikuisis P, Mclellan TM, Selkirk G. Perceptual versus physiological heat strain during exercise-heat stress. Medicine & Science in Sports & Exercise. 2002;34(9):1454-61.

Golbabaee F,Omidvari M. man and thermal environments. Tehran University Press. 2002;80-90، 190-25. Tehran, Iran (Persian).

Dehghan H, Mortazavi SB, Jafari MJ, Maracy MR. Combination of wet bulb globe temperature and heart rate in hot climatic conditions: The practical guidance for a better estimation of the heat strain. International Journal of Environmental Health Engineering. 2012;1(1):18-23.

Malchaire J, Gebhardt H, Piette A. Strategy for evaluation and prevention of risk due to work in thermal environments. Annals of occupational hygiene. 1999;43(5):367-76.

Rastogi S, Gupta B, Husain T. Wet-bulb globe temperature index: a predictor of physiological strain in hot environments. Occupational Medicine. 1992;42(2):93-97.

Gallagher Jr M, Robertson RJ, Goss FL, Nagle-Stilley EF, Schafer MA, Suyama J, et al. Development of a perceptual hyperthermia index to evaluate heat strain during treadmill exercise. European journal of applied physiology. 2012;112(6):2025-34.

Habibi P, Dehghan H, Rezaei S , Maghsoudi K . Relationship between physiological strain index and wet bulb globe temperature index in women in the climate chamber. Journal of Health System Research. 2014;8(3):1-3. (Persian).

Latzka WA, Sawka MN, Montain SJ, Skrinar GS, Fielding RA, Matott RP, et al. Hyperhydration: tolerance and cardiovascular effects during uncompensable exercise-heat stress. Journal of Applied Physiology. 1998;84(6):1858-64.

Hostler D, Gallagher Jr M, Goss FL, Seitz JR, Reis SE, Robertson RJ, et al. The effect of hyperhydration on physiological and perceived strain during treadmill exercise in personal protective equipment. European journal of applied physiology. 2009;105(4):607-13.

Habibi P, Dehghan H, Rezaei S, Maghsoudi K. Thermal, physiological strain index and perceptual responses in iranian muslim women under thermal condition in order to guide in prevention of heat stress. Iran Journal Health Safe Environment. 2014;1(4):172-76.

Schaeffer SA, Darby LA, Browder KD. Differentiated ratings of perceived exertion and physiological responses during aerobic dance steps by impact/type of arm movement. Perceptual and motor skills. 2000;90(2):457-71.

Iranian Journal of Health, Safety and Environment e-ISSN: :2345-5535 Iran university of Medical sciences, Tehran, Iran