Evaluation of Heat Stress among Farmers Using Environmenta l and Biological Monitoring: A study in North of Iran


In this  cross sectional s tudy carried out in s pring and s ummer, 79 farmers working  in different  job  pos itions including agriculture, hus bandry and horticulture in north of Iran were participa ted. Evaluation of the heat s tres s was conducted us ing Wet Bulb Glob Temperature (WBGT) index according ISO7243 and heat s train evaluation us ing  meas uring  the  individual  phys iological  res pons es  including  aural,  oral  and  mean  s kin  temperatures according ISO 9886. The demographic characteris tics of the s ubjects s uch as age, job experience, BMI and body area were als o gathered  through a ques tionnaire. In general, the s ubjects were in middle ages  (38.44±8.86 yr) and mean and s tandard deviation of years  of expe rience were almos t high (17.49±9.41 yr), too. The s tatis tical analys is was performed  by SPSS 18 s oftware. The  res ults  s howed that the WBGT index values  had  ranging from 24 to  32.6°C in  s ummer  regardles s  of clothing  ins ulation,  metabolic  rate  and  work  res t  regimens .  Of cours e, by correction of thes e parameters the WBGT will accompany with an incens ement. Convers ely, the heat s train monitoring revealed that in no cas e the aural and oral temperatures are higher than the limit allowed. The bes t correlation  coefficient  was obtained  for aural temperature  and WBGT index (r= 0.84, P< 0.001). It  s eems that evaluation of hot and humid environment us ing WBGT index can be as s ociated with an overes timation and encountered our judgment about the environmental condition with a s ignificant error.

Mairiaux P, Malchaire J. Workers self-pacing in hot conditions: a case study. Appl Ergon 1985; 16(2): 85-90.

Dehghan H, Mortazavi S, Jafari M, Maracy M. Combination of wet bulb globe temperature and heart rate in hot climatic conditions: The practical guidance for a better estimation of the heat strain. Int J Environ Health Eng 2012; 1(1): 18-23.

Miller V, Bates G, Schneider JD, Thomsen J. Self-pacing as a protective mechanism against the effects of heat stress. Ann Occup Hyg 2011; 55(5): 548-55.

Dehghan H, Mortazavi B, Jafari MJ, Maracy MR. Evaluation of wet bulb globe temperature index for estimation of heat strain in hot/humid conditions in the Persian Gulf. J Res Med Sci 2012; 17(12): 1108.

Moran DS, Epstein Y. Evaluation of the environmental stress index (ESI) for hot/dry and hot/wet climates. Ind Health 2006; 44(3): 399-403.

Bouchama A, Knochel JP. Heat stroke. New Engl J Med 2002; 346(25): 1978-88.

Bhattacharya R, Pal S, Biswas G, Karmakar S, Banik R. An estimation of heat stress in tropics. Int J Eng Sci Tech 2012; 4(10): 4302-7.

Masuodian SA. Investigation of Iran temperature at past half- century. Res Geogr 2005; 54 (4): 29-45.

Tghavi F. Trends in indices of temperature and precipitation extreme in Iran. PhD thesis, University of Tehran, Tehran, Iran, 2005.

Farajzadeh M, Ahmad abadi A. Assessment and zoning of tourism climate of Iran using tourism climate index (TCI). Res Geogr 2010; 71: 31-42.

Parsons K. Human thermal environments: the effects of hot, moderate, and cold environments on human health, comfort and performance. 2nd ed, Taylor and Francis Group, New York, USA, 2003.

ISO 7243. Ergonimics of the thermal environment-Estimation of the heat stress on working man, based on the WBGT-index. International Standard Organization, 1989.

Yaglon CP, Minard D. Control of heat casuiilties at military training centers. Arch Ind Health 1957; 16: 302-5.

Mohamed M. Heat stress in date-palm workplaces a study in the Algerian oases. Afr Newslett Occup Health Saf 2004; 14(2): 34-7.

Donoghue A, Bates G. The risk of heat exhaustion at a deep underground metalliferous mine in relation to body-mass index and predicted VO2max. Occup Med 2000; 50(4): 259-63.

Bedno SA, Li Y, Han W, Cowan DN, Scott CT, Cavicchia MA, et al. Exertional heat illness among overweight US army recruits in basic training. Aviat Space Environ Med 2010; 81(2): 107-11.

Kenney WL, Munce TA. Invited review: Aging and human temperature regulation. J Appl Physiol 2003; 95(6): 2598-603.

Marszałek A, Konarska M, Bugajska J. Assessment of work ability in a hot environment of workers of different ages. Int Congr 2005; Elsevier.

Nakai S, Shinzato K, Morimoto T. Epidemiological analysis of heat disorders in Japan—An analysis of gleaned cases from newspaper report between 1990 and 1994. Jpn J Biometeorol 1996; 33: 71-7.

Budd GM. Wet-bulb globe temperature (WBGT)—Its history and its limitations. J Sci Med Sport 2008; 11(1): 20-32.

Motamedzade M, Azari MR. Heat stress evaluation using environmental and biological monitoring. Pakistan J Biol Sci 2006; 9(3): 457-9.

Childs C, Harrison R, Hodkinson C. Tympanic membrane temperature as a measure of core temperature. Arch Dis Child 1999; 80(3): 262-6.

Lee JY, Nakao K, Takahashi N, Son SY, Bakri I, Tochihara Y. Validity of infrared tympanic temperature for the evaluation of heat strain while wearing impermeable protective clothing in hot environments. Ind health 2011; 49(6): 714-25

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Heat stress Biological monitoring Farmer WBGT index

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HEIDARI H, GOLBABAEI F, SHAMSIPOUR A, RAHIMI FOROUSHANI A, GAEINI A. Evaluation of Heat Stress among Farmers Using Environmenta l and Biological Monitoring: A study in North of Iran. Int J Occup Hyg. 2015;7(1):1-9.