Effects of thermal stress on human performance

Swedish Defence Research Establishment, Karlstad, Sweden.
Scandinavian Journal of Work, Environment & Health (Impact Factor: 3.45). 02/1989; 15 Suppl 1:27-33.
Source: PubMed


Experimental evidence indicates that even relatively mild thermal stress may affect human performance. Tasks requiring manual dexterity and muscular strength are clearly impaired by cold exposure, while decrements in vigilance performance and endurance are well documented effects of heat stress. The considerable variation in results regarding the effects of thermal stress may, to some extent, be attributable to complex interactions between exposure conditions, task characteristics, and individual factors. In the present paper the relevance of some of the earlier research work on heat and cold stress is evaluated in the light of the practical and theoretical implications of more recent findings. Current work regarding the nature and extent of the effects of thermal stress on more complex performance is discussed. Attention is also focused on the significance of individual skill and training experience for performance under unfavorable conditions.

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    • "It remains unclear, however, this relationship is generated by the color itself or Due to acclimation, short exposure of heat and cold is considered to have little or no effect on performance (Hancock & Vasmatzidis, 2003). However other studies see short exposure as even worse, due to acclimation (Enander, 1989; Pilcher et al., 2002). Even an improvement on simple tasks under short exposure of heat could be identified (Nunneley, Dowd, Myhre, Stribley, & McNee, 1979). "
    Full-text · Article · Feb 2016
    • "Heat stress can produce detrimental effects on motor response, and since most cognitive tasks require a motor response, some cognitive deficiencies may be attributed to decreased motor perform- ance[14]. The association between t core (and/or its rate of change) and performance loss thus appears to be theoretically well established[11,12]and corroborated by several experimental studies151617. The skin temperature is also widely recognized as playing a significant role in performance loss[18]. "
    [Show abstract] [Hide abstract] ABSTRACT: Purpose: This paper investigates the thermal conditions inside a passenger car driven after it was left a few hours in a shade-less parking lot, and the related implications for the driving performance. Materials and methods: Experimental results for twelve tests carried out in four different vehicles are presented and discussed. Each test is characterized by means of the predicted core temperature tcore of the driver after 60 minutes, as calculated by a heat stress model. The fractional performance loss is calculated by adjusting existing algorithms for office tasks to accommodate literature data on driving-related tasks, and then re-casting the algorithm as a function of tcore instead of the air temperature ta. Results: Based on measured temperatures and humidities, fractional performance losses up to 50% are predicted even for relatively simple tasks such as keeping the vehicle on a straight course. Performance losses in excess of 75% are predicted, under the most extreme thermal conditions, for demanding tasks, such as correctly identifying a signal and reacting in due time. Conclusions: The implementation in technical standards on heat stress assessment of two new thresholds is recommended. The lower threshold, to be set at tcore ≅ 37.1 °C, is aimed at ensuring that the subject is able to carry out demanding mental tasks without appreciable performance loss, while the higher threshold, to be set at tcore ≅ 37.2 °C applies to simpler tasks.
    No preview · Article · Jun 2014 · International Journal of Hyperthermia
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    • "Participants mentioned feeling “dizzy” if they did not drink enough water. Decrements in vigilance and endurance during heat exposure have also been described [29], which could increase the risk of falls from ladders and other equipment. Several epidemiologic studies have suggested that there is a relationship between occupational heat stress and injury [30,31]. "
    [Show abstract] [Hide abstract] ABSTRACT: Heat-related illness (HRI) is an important cause of non-fatal illness and death in farmworkers. We sought to identify potential barriers to HRI prevention and treatment in Latino farmworkers. We conducted three semi-structured focus group discussions with 35 Latino farmworkers in the Central Washington, USA area using participatory rural appraisal techniques. Interviews were audio taped and transcribed in Spanish. Three researchers reviewed and coded transcripts and field notes, and investigator triangulation was used to identify relevant themes and quotes. Although the majority of participants in our study reported never receiving formal HRI training, most participants were aware that extreme heat can cause illness and were able to accurately describe HRI symptoms, risk factors, and certain prevention strategies. Four main observations regarding farmworkers' HRI-relevant beliefs and attitudes were identified: 1) farmworkers subscribe to varying degrees to the belief that cooling treatments should be avoided after heat exposure, with some believing that such treatments should be avoided after heat exposure, and others encouraging the use of such treatments; 2) the desire to lose weight may be reflected in behaviors that promote increased sweating; 3) highly caffeinated energy drinks are preferred to increase work efficiency and maintain alertness; and 4) the location of drinking water at work (e.g. next to restrooms) and whether water is clean, but not necessarily chemically-treated, are important considerations in deciding whether to drink the water provided at worksites. We identified potential barriers to HRI prevention and treatment related to hydration, certain HRI treatments, clothing use, and the desire to lose weight among Latino farmworkers. Strategies to address potential barriers to HRI prevention and treatment in this population may include engineering, administrative, and health education and health promotion strategies at individual, workplace, community, and societal levels. Although farmworkers in our study were able to describe HRI risk factors, reported practices were not necessarily consistent with reported knowledge. Further study of potential knowledge-behavior gaps may uncover opportunities for additional HRI prevention strategies. Farmworkers and employers should be included in the development and evaluation of interventions to prevent HRI.
    Full-text · Article · Oct 2013 · BMC Public Health
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