title: The influence of occupational heat exposure on cognitive performance and blood level of stress hormones: a field study report.
abstract: BACKGROUND
  This article aimed to investigate the effect of heat stress on cognitive performance and the blood concentration of stress hormones among workers of a foundry plant.
  
  
  METHODS
  Seventy workers within the exposed (35 people) and unexposed (35 people) groups were studied. The wet bulb globe temperature (WBGT) index was measured for heat stress assessment. The cognitive performance tests were conducted using the Stroop color word test (SCWT) before and during working hours. For the assessment of the serum level of cortisol and the plasma level of adrenaline and noradrenaline, blood samples were taken during working hours from both groups.
  
  
  RESULTS
  Only for SCWT III was there a significant relationship between heat stress and test duration, error rate and reaction time. The laboratory test results revealed significantly higher concentrations of cortisol, adrenaline and noradrenaline in the exposed subjects than in the unexposed group. There existed a positive correlation between cortisol, adrenaline, noradrenaline and WBGT index and also test duration and reaction time of SCWT III, and number of errors of SCWT I, SCWT II and SCWT III during work.
  
  
  CONCLUSIONS
  Heat stress can lead to an increase in the blood level of stress hormones, resulting in cognitive performance impairment.
authors.affiliation: a Department of Occupational Health , Tehran University of Medical Sciences , Iran.
authors.forename: Adel
authors.initials: A
authors.lastname: Mazlomi
authors.affiliation: a Department of Occupational Health , Tehran University of Medical Sciences , Iran.
authors.forename: Farideh
authors.initials: F
authors.lastname: Golbabaei
authors.affiliation: a Department of Occupational Health , Tehran University of Medical Sciences , Iran.
authors.forename: Somayeh
authors.initials: S
authors.lastname: Farhang Dehghan
authors.affiliation: a Department of Occupational Health , Tehran University of Medical Sciences , Iran.
authors.forename: Marzieh
authors.initials: M
authors.lastname: Abbasinia
authors.affiliation: a Department of Occupational Health , Tehran University of Medical Sciences , Iran.
authors.forename: Somayeh
authors.initials: S
authors.lastname: Mahmoud Khani
authors.affiliation: b Department of Clinical Biochemistry , Tehran University of Medical Sciences , Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ansari
authors.affiliation: c Department of Epidemiology and Biostatistics , Tehran University of Medical Sciences , Iran.
authors.forename: Mostafa
authors.initials: M
authors.lastname: Hosseini
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001336:Automobiles; D003071:Cognition; D004837:Epinephrine / Q000097:blood; D018882:Heat Stress Disorders / Q000097:blood / Q000503:physiopathology / Q000523:psychology*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007492:Iran; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D013312:Stress, Physiological; D057190:Stroop Test
chemical_list: D006854:Hydrocortisone; D004837:Epinephrine
keywords: cognitive performance; foundry industry; heat stress; stress hormones