title: Validation of Perceptual Strain Index to Evaluate the Thermal Strain in Experimental Hot Conditions.
abstract: BACKGROUND
  The incidence of heat stress is one of the most common problems in workplaces and industries. Many heat stress indices have been developed, and these indices have some disadvantages. The purpose of this study is to validate the perceptual strain index (PeSI) in experimental hot conditions.
  
  
  METHODS
  This study is of cross-sectional carried out on 15 men at five different thermal conditions (35°C, 30°C, 27°C, 24°C, and 21°C) in a climate chamber and on a treadmill at three levels of light (2.4 kph), medium (4.8 kph) and heavy activity (6.3 kph). Heart rate and oral temperature were respectively measured to calculate the physiological strain index. Also, thermal sensation and rate perceive exertion were respectively measured to calculate the PeSI. Finally, the correlation between the indices was analyzed using Pearson correlation test and regression analysis.
  
  
  RESULTS
  Pearson correlation test showed a high correlation (r = 0.94) between the PeSI and physiological strain index (P = 0/001). It was also observed a high correlation between the PeSI and the oral temperature (r = 0.78, P = 0/001) and the heart rate (r = 0.90, P = 0/001). In addition, there was found a moderate correlation (r = 0.71) between the PeSI and the wet bulb glob temperature (P = 0/001). However, there was no correlation between the PeSI and the body mass index (r = 0.0009, P = 0.79).
  
  
  CONCLUSIONS
  The research findings showed when there is no access to other forms of methods to evaluate the heat stress, it can be used the PeSI in evaluating the strain because of its favorable correlation with the thermal strain.
authors.affiliation: Department of Occupational Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Habibollah
authors.initials: H
authors.lastname: Dehghan
authors.affiliation: Department of Occupational Health, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Ayoub
authors.initials: A
authors.lastname: Ghanbary Sartang
keywords: Evaluation of thermal strain; hot experimental conditions; perceptual strain index; physiological strain index