Assessment of Occupational Heat Strain

Details

• Personal Author:
  Wan M
• Description:
  Assessment of heat strain considers an individual's tolerance and indicates the risk and physiological cost of working in hot environments. This study evaluated the discrimination ability of metrics of heat strain. The null hypotheses were that (1) the metrics individually could not discriminate between acceptable and unacceptable heat strain, (2) there were no significant differences among these metrics, and (3) there were no significant differences in the applicability of the metrics due to clothing or heat stress level. The experimental design was a case crossover. Clothing and heat stress level were potential confounders. Two clothing ensembles were work clothes and vapor-barrier coveralls with hood. Two heat stress levels for a moderate metabolic rate were 5 degrees C-WBGT and 10 degrees C-WBGT above the Threshold Limit Value adjusted for clothing. Eight male and four female acclimated individuals (age 18-36 years) participated. Four experimental trials were randomized in sequence. The transition point, when a participant's status changed from control (acceptable heat strain) to case (unacceptable), was the first occurrence of rectal temperature equal to or greater than 38.5 degrees C, heart rate equal to or greater than 90% of maximum, or volitional fatigue. The metrics were rectal, ear canal, oral, and disk temperatures, heart rate including moving time averages of 5, 10, 20, 30 and 45 minutes, recovery heart rate, and physiological strain index. The data at the transition point were the case data; the data 10 minutes prior to that point were the control data. Analyses used primarily receiver operating characteristic (ROC) curves, which indicated the ability to distinguish acceptable from unacceptable heat strain. Further analyses included factorial analysis of variance and exact conditional logistic regression. Based on the ROC curve analyses, the physiological metrics can distinguish between acceptable and unacceptable heat strain with average area under the curves between 0.529 and 0.861. While there were no differences among the metrics based on the 95% confidence intervals of the areas under the curve, the results were compromised by low power. Based on ANOVA and logistic regression, clothing did not influence the metrics. There were insufficient data to evaluate the role of heat stress level. [Description provided by NIOSH]
• Subjects:
  Cardiovascular System Environmental Exposure Heat Stress Disorders Hot Temperature Occupational Health Safety Temperature
• Keywords:
  Author Keywords: Core Temperature Clothing Ear Canal Temperature Exposure Levels Heart Rate Heat Exposure Heat Stress Hot Environments Oral Temperature Physiological Effects Physiological Strain Index Recovery Heart Rate Rectal Temperature Temperature Effects Temperature Measurement Volitional Fatigue

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• ISBN:
  9780542819711
• Publisher:
  ProQuest LLC.
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Dissertation
• Place as Subject:
  Florida ; OSHA Region 4
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• NIOSHTIC Number:
  nn:20057584
• Citation:
  Ann Arbor, MI: ProQuest LLC., 2006 Jul; :3230414
• Federal Fiscal Year:
  2006
• Performing Organization:
  Sunshine Education Research Center, University of South Florida, Tampa
• Peer Reviewed:
  False
• Start Date:
  19970701
• Source Full Name:
  Assessment of occupational heat strain
• End Date:
  20020630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:6572a2c362d7c576991978446e9271efb5747e9964647f287c3066e9a956cb0cece04a158096460ad79840281ff7a91fe53739625de5a3a46ad13d77889d8739
• Download URL:
  https://stacks.cdc.gov/view/cdc/214869/cdc_214869_DS1.pdf
• File Type:
  [PDF - 321.23 KB ]