Author:
Kampmann Bernhard,Bröde Peter
Abstract
AbstractFor time- and cost-efficient heat stress assessment procedures at workplaces or in experimental studies, short-time measurement periods (e.g. 1 h) are sometimes employed in lieu of whole shift observations assuming that the short time period will provide valid figures of equilibrium physiological responses. We studied the influence of exposure duration on physiological heat strain considering the modifying effects of clothing and heat acclimation using a database of 564 climatic chamber exposures performed by 28 young males under heat stress conditions with widely varying air temperature and humidity levels. We compared heart rates, rectal and mean skin temperatures, and sweat rates recorded after 1 h with the values averaged over the third hour of exposure representing steady-state. One-hour measurements agreed with equilibrium values for rather low strain levels only, with heart rates below 100 bpm and rectal temperatures below 37.2 °C. On average, one-hour values underestimated all heat strain parameters. This underestimation error was only moderately influenced by clothing and heat acclimation status, but increased significantly with air temperature and humidity, reaching considerable magnitude under hot-humid conditions associated with elevated heat strain. Regression analyses of the prediction error depending on the equilibrium response revealed that underestimation increased with equilibrium strain level. This correlation was strongest for heart rate and core temperature, and was shown to potentially cause a misclassification of hazardous working conditions as safe by given heat strain criteria.Practical Relevance: The severe underestimation of heat strain due to short measurement periods, as observed under hot-humid conditions and/or when associated with high physiological strain, will immediately impact the exposed personnel, but will also inform occupational health professionals and standard writers regarding the heat stress assessment for work shifts with high activity levels or with protective clothing.
Funder
Bergische Universität Wuppertal
Publisher
Springer Science and Business Media LLC
Reference65 articles.
1. Bates D, Mächler M, Bolker B, Walker S (2015) Fitting linear mixed-effects models using lme4. J Stat Soft 67:48
2. Bernard TE, Caravello V, Schwartz SW, Ashley CD (2008) WBGT clothing adjustment factors for four clothing ensembles and the effects of metabolic demands. J Occup Environ Hyg 5:1–5
3. Bland JM, Altman DG (1995) Comparing methods of measurement: why plotting difference against standard method is misleading. Lancet 346:1085–1087
4. Bröde P, Havenith G, Wang X, Candas V, den Hartog E, Griefahn B et al (2008) Non-evaporative effects of a wet mid layer on heat transfer through protective clothing. Eur J Appl Physiol 104:341–349
5. Bröde P, Fiala D, Kampmann B (2017) Considering varying clothing, activities and exposure times with the Universal Thermal Climate Index UTCI. International Society of Biometeorology (Ed) 21st International Congress of Biometeorology. Durham University, Durham, pp 57–60
Cited by
3 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献