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Ioannou LG, Tsoutsoubi L, Mantzios K, Gkikas G, Piil JF, Dinas PC, Notley SR, Kenny GP, Nybo L, Flouris AD. The Impacts of Sun Exposure on Worker Physiology and Cognition: Multi-Country Evidence and Interventions. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:7698. [PMID: 34300148 PMCID: PMC8303297 DOI: 10.3390/ijerph18147698] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 07/12/2021] [Accepted: 07/14/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND A set of four case-control (n = 109), randomized-controlled (n = 7), cross-sectional (n = 78), and intervention (n = 47) studies was conducted across three countries to investigate the effects of sun exposure on worker physiology and cognition. METHODS Physiological, subjective, and cognitive performance data were collected from people working in ambient conditions characterized by the same thermal stress but different solar radiation levels. RESULTS People working under the sun were more likely to experience dizziness, weakness, and other symptoms of heat strain. These clinical impacts of sun exposure were not accompanied by changes in core body temperature but, instead, were linked with changes in skin temperature. Other physiological responses (heart rate, skin blood flow, and sweat rate) were also increased during sun exposure, while attention and vigilance were reduced by 45% and 67%, respectively, compared to exposure to a similar thermal stress without sunlight. Light-colored clothes reduced workers' skin temperature by 12-13% compared to darker-colored clothes. CONCLUSIONS Working under the sun worsens the physiological heat strain experienced and compromises cognitive function, even when the level of heat stress is thought to be the same as being in the shade. Wearing light-colored clothes can limit the physiological heat strain experienced by the body.
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Affiliation(s)
- Leonidas G. Ioannou
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (L.T.); (K.M.); (G.G.); (P.C.D.)
- Department of Nutrition, Exercise and Sports, August Krogh Building, University of Copenhagen, 2100 Copenhagen, Denmark; (J.F.P.); (L.N.)
| | - Lydia Tsoutsoubi
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (L.T.); (K.M.); (G.G.); (P.C.D.)
| | - Konstantinos Mantzios
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (L.T.); (K.M.); (G.G.); (P.C.D.)
| | - Giorgos Gkikas
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (L.T.); (K.M.); (G.G.); (P.C.D.)
| | - Jacob F. Piil
- Department of Nutrition, Exercise and Sports, August Krogh Building, University of Copenhagen, 2100 Copenhagen, Denmark; (J.F.P.); (L.N.)
| | - Petros C. Dinas
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (L.T.); (K.M.); (G.G.); (P.C.D.)
| | - Sean R. Notley
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (S.R.N.); (G.P.K.)
| | - Glen P. Kenny
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (S.R.N.); (G.P.K.)
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - Lars Nybo
- Department of Nutrition, Exercise and Sports, August Krogh Building, University of Copenhagen, 2100 Copenhagen, Denmark; (J.F.P.); (L.N.)
| | - Andreas D. Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (L.T.); (K.M.); (G.G.); (P.C.D.)
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (S.R.N.); (G.P.K.)
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Park S, Tuller SE. Human body area factors for radiation exchange analysis: standing and walking postures. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2011; 55:695-709. [PMID: 21080004 DOI: 10.1007/s00484-010-0385-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 10/10/2010] [Accepted: 10/19/2010] [Indexed: 05/30/2023]
Abstract
Effective radiation area factors (f (eff)) and projected area factors (f (p)) of unclothed Caucasians' standing and walking postures used in estimating human radiation exchange with the surrounding environment were determined from a sample of adults in Canada. Several three-dimensional (3D) computer body models were created for standing and walking postures. Only small differences in f (eff) and f (p) values for standing posture were found between gender (male or female) and body type (normal- or over-weight). Differences between this study and previous studies were much larger: ≤0.173 in f (p) and ≤0.101 in f (eff). Directionless f (p) values for walking posture also had only minor differences between genders and positions in a stride. However, the differences of mean directional f (p) values of the positions dependent on azimuth angles were large enough, ≤0.072, to create important differences in modeled radiation receipt. Differences in f (eff) values were small: 0.02 between the normal-weight male and female models and up to 0.033 between positions in a stride. Variations of directional f (p) values depending on solar altitudes for walking posture were narrower than those for standing posture. When both standing and walking postures are considered, the mean f (eff) value, 0.836, of standing (0.826) and walking (0.846) could be used. However, f (p) values should be selected carefully because differences between directional and directionless f (p) values were large enough that they could influence the estimated level of human thermal sensation.
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Affiliation(s)
- Sookuk Park
- Climate Laboratory, Department of Geography, University of Victoria, BC, Canada.
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The evolution of the upright posture and gait--a review and a new synthesis. Naturwissenschaften 2010; 97:241-63. [PMID: 20127307 PMCID: PMC2819487 DOI: 10.1007/s00114-009-0637-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 11/27/2009] [Accepted: 12/02/2009] [Indexed: 11/01/2022]
Abstract
During the last century, approximately 30 hypotheses have been constructed to explain the evolution of the human upright posture and locomotion. The most important and recent ones are discussed here. Meanwhile, it has been established that all main hypotheses published until the last decade of the past century are outdated, at least with respect to some of their main ideas: Firstly, they were focused on only one cause for the evolution of bipedality, whereas the evolutionary process was much more complex. Secondly, they were all placed into a savannah scenario. During the 1990s, the fossil record allowed the reconstruction of emerging bipedalism more precisely in a forested habitat (e.g., as reported by Clarke and Tobias (Science 269:521-524, 1995) and WoldeGabriel et al. (Nature 412:175-178, 2001)). Moreover, the fossil remains revealed increasing evidence that this part of human evolution took place in a more humid environment than previously assumed. The Amphibian Generalist Theory, presented first in the year 2000, suggests that bipedalism began in a wooded habitat. The forests were not far from a shore, where our early ancestor, along with its arboreal habits, walked and waded in shallow water finding rich food with little investment. In contrast to all other theories, wading behaviour not only triggers an upright posture, but also forces the individual to maintain this position and to walk bipedally. So far, this is the only scenario suitable to overcome the considerable anatomical and functional threshold from quadrupedalism to bipedalism. This is consistent with paleoanthropological findings and with functional anatomy as well as with energetic calculations, and not least, with evolutionary psychology. The new synthesis presented here is able to harmonise many of the hitherto competing theories.
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