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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    • "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]. "
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    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.
    BMC Public Health 10/2013; 13(1):1004. DOI:10.1186/1471-2458-13-1004 · 2.26 Impact Factor
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    • "Temperature dependency in motor skill learning, , 4 Wilby (1995) reported improvements in shooting performance with forearm cooling. These 1 equivocal effects might be explained by differences in the intensity and length of thermal 2 exposure across experimental conditions (Hancock, Ross, & Szalma, 2007; Pilcher, Nadler, & 3 Busch, 2002; Enander, 1989). The likelihood that performance will be degraded depends on the 4 extent to which temperature conditions form a thermal stressor, in terms of deviation from some 5 optimal-level of function or comfort. "
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    ABSTRACT: The present study investigated the role of temperature as a contextual condition for motor skill learning. Precision grip task training occurred while forearm cutaneous temperature was either heated (40-45 °C) or cooled (10-15 °C). At test, temperature was either reinstated or changed. Performance was comparable between training conditions while at test, temperature changes decreased accuracy, especially after hot training conditions. After cold training, temperature change deficits were only evident when concurrent force feedback was presented. These findings are the first evidence of localized temperature dependency in motor skill learning in humans. Results are not entirely accounted for by a context-dependent memory explanation and appear to represent an interaction of neuromuscular and sensory processes with the temperature present during training and test.
    Journal of Motor Behavior 03/2012; 44(2):105-13. DOI:10.1080/00222895.2012.654522 · 1.42 Impact Factor
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    • "Local cooling of the hand and arm decreases manual performance through both physical and neuromuscular pathways (Enander 1998; Rissanen and Rintamaki 2000). Local cooling decreases flexibility (LeBlanc et al. 1960) due to increased viscosity within joints and soft tissues that interferes with smooth joint movements (Enander 1998; Rissanen and Rintamaki 2000). Cold also affects muscle activity through decreased ATP utilization, enzyme activity , calcium and acetylcholine release, and delayed cross bridge formation (Giesbrecht and Bristow 1992). "
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    ABSTRACT: Cold water immersion and protective gloves are associated with decreased manual performance. Although neoprene gloves slow hand cooling, there is little information on whether they provide sufficient protection when diving in cold water. Nine divers wearing three-fingered neoprene gloves and dry suits were immersed in water at 25 and 4 degrees C, at depths of 0.4 msw (101 kPa altitude adjusted) and 40 msw (497 kPa) in a hyperbaric chamber. Skin temperatures were measured at the fingers, hand, forearm, chest and head. Grip strength, tactile sensitivity and manual dexterity were measured at three time intervals. There was an exponential decay in finger and back of hand skin temperatures with exposure time in 4 degrees C water. Finger and back of hand skin temperatures were lower at 40 msw than at 0.4 msw (P < 0.05). There was no effect of pressure or temperature on grip strength. Tactile sensitivity decreased linearly with finger skin temperature at both pressures. Manual dexterity was not affected by finger skin temperature at 0.4 msw, but decreased with fall in finger skin temperature at 40 msw. Results show that neoprene gloves do not provide adequate thermal protection in 4 degrees C water and that impairment of manual performance is dependent on the type of task, depth and exposure time.
    Arbeitsphysiologie 03/2008; 104(2):237-44. DOI:10.1007/s00421-008-0715-9 · 2.19 Impact Factor
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