Hayden W Hess, M Jo Hite, Molly E Heikkinen, Macie L Tarr, Erica Tourula, Blair D Johnson, David Hostler, Zachary J Schlader
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引用次数: 0
Abstract
Background: Occupational heat stress recommendations aim to achieve thermal equilibrium and keep core temperature (Tc) below 38.0°C. We assessed the recommended alert limit curves when: (1) work-rest ratios are adjusted based on wet-bulb globe temperature (WBGT) at a fixed rate of metabolic heat production (Hprod) and (2) Hprod is adjusted based on WBGT at a fixed work-rest ratio. We tested the hypothesis that adhering to occupational heat stress recommendations results in thermal equilibrium and prevents TC from exceeding 38.0°C.
Methods: Unacclimated adults completed 4-hour exposures at a fixed WBGT, Hprod, and work-rest ratio. There were six iterations of compliant trials (n = 70 observations; A: 24.1°C, 431 W, 60:0 min; B: 26.6°C, 461 W, 45:15 min; C: 28.4°C, 462 W, 30:30 min; D: 29.7, 453 W, 15:45 min; E: 27.3°C, 412 W, 30:30 min; F: 31.6°C, 290 W, 30:30 min) and two iterations of noncompliant trials (n = 24 observations; G: 31.6°C, 413 W, 30:30 min; H: 36.1°C, 453 W, 15:45 min).
Results: Mean and peak TC across the compliant trials were 37.6°C ± 0.3°C and 37.9°C ± 0.3°C. Thus, 65/70 (93%) and 44/70 (63%) trials did not exceed a mean or peak core TC of 38.0°C. Mean and peak TC across the noncompliant trials exceeded 38.0°C in all trials. The rate of heat gain differed between compliant and noncompliant trials (0.08°C ± 0.07°C/h vs. 0.41°C ± 0.34°C/h; p < 0.0001) but on average thermal equilibrium was < 0.1°C/h in the compliant trials.
Conclusion: Compliance with the occupational heat stress recommendations resulted in thermal equilibrium and mitigated the development of excessive heat strain.
期刊介绍：
American Journal of Industrial Medicine considers for publication reports of original research, review articles, instructive case reports, and analyses of policy in the fields of occupational and environmental health and safety. The Journal also accepts commentaries, book reviews and letters of comment and criticism. The goals of the journal are to advance and disseminate knowledge, promote research and foster the prevention of disease and injury. Specific topics of interest include: occupational disease; environmental disease; pesticides; cancer; occupational epidemiology; environmental epidemiology; disease surveillance systems; ergonomics; dust diseases; lead poisoning; neurotoxicology; endocrine disruptors.
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