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The origin, significance and plasticity of the thermoeffector thresholds: Extrapolation between humans and laboratory rodents. J Therm Biol 2019; 85:102397. [DOI: 10.1016/j.jtherbio.2019.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 08/05/2019] [Accepted: 08/05/2019] [Indexed: 01/07/2023]
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Indirect hand and forearm vasomotion: Regional variations in cutaneous thermosensitivity during normothermia and mild hyperthermia. J Therm Biol 2017; 65:95-104. [DOI: 10.1016/j.jtherbio.2017.02.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 02/24/2017] [Accepted: 02/24/2017] [Indexed: 11/21/2022]
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Wingo JE, Low DA, Keller DM, Kimura K, Crandall CG. Combined facial heating and inhalation of hot air do not alter thermoeffector responses in humans. Am J Physiol Regul Integr Comp Physiol 2015; 309:R623-7. [PMID: 26157054 PMCID: PMC4591374 DOI: 10.1152/ajpregu.00018.2015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 07/06/2015] [Indexed: 11/22/2022]
Abstract
The influence of thermoreceptors in human facial skin on thermoeffector responses is equivocal; furthermore, the presence of thermoreceptors in the respiratory tract and their involvement in thermal homeostasis has not been elucidated. This study tested the hypothesis that hot air directed on the face and inhaled during whole body passive heat stress elicits an earlier onset and greater sensitivity of cutaneous vasodilation and sweating than that directed on an equal skin surface area away from the face. Six men and two women completed two trials separated by ∼1 wk. Participants were passively heated (water-perfused suit; core temperature increase ∼0.9°C) while hot air was directed on either the face or on the lower leg (counterbalanced). Skin blood flux (laser-Doppler flowmetry) and local sweat rate (capacitance hygrometry) were measured at the chest and one forearm. During hot-air heating, local temperatures of the cheek and leg were 38.4 ± 0.8°C and 38.8 ± 0.6°C, respectively (P = 0.18). Breathing hot air combined with facial heating did not affect mean body temperature onsets (P = 0.97 and 0.27 for arm and chest sites, respectively) or slopes of cutaneous vasodilation (P = 0.49 and 0.43 for arm and chest sites, respectively), or the onsets (P = 0.89 and 0.94 for arm and chest sites, respectively), or slopes of sweating (P = 0.48 and 0.65 for arm and chest sites, respectively). Based on these findings, respiratory tract thermoreceptors, if present in humans, and selective facial skin heating do not modulate thermoeffector responses during passive heat stress.
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Affiliation(s)
- Jonathan E Wingo
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas; Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas; Department of Kinesiology, University of Alabama, Tuscaloosa, Alabama
| | - David A Low
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas; Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas; Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - David M Keller
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas; Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas; Department of Kinesiology, University of Texas at Arlington, Arlington, Texas; and
| | - Kenichi Kimura
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas; Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas; Department of Health Sciences, Kansai University of Health Sciences, Osaka, Japan
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas; Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas;
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Considerations for the measurement of core, skin and mean body temperatures. J Therm Biol 2014; 46:72-101. [DOI: 10.1016/j.jtherbio.2014.10.006] [Citation(s) in RCA: 228] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 10/24/2014] [Accepted: 10/27/2014] [Indexed: 11/23/2022]
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Sawka MN, Leon LR, Montain SJ, Sonna LA. Integrated Physiological Mechanisms of Exercise Performance, Adaptation, and Maladaptation to Heat Stress. Compr Physiol 2011; 1:1883-928. [DOI: 10.1002/cphy.c100082] [Citation(s) in RCA: 299] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Cheung SS. Interconnections between thermal perception and exercise capacity in the heat. Scand J Med Sci Sports 2010; 20 Suppl 3:53-9. [DOI: 10.1111/j.1600-0838.2010.01209.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Cheung SS. Neuropsychological determinants of exercise tolerance in the heat. PROGRESS IN BRAIN RESEARCH 2007; 162:45-60. [PMID: 17645914 DOI: 10.1016/s0079-6123(06)62004-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Traditionally, exercise in the heat has been assumed to be primarily limited by cardiovascular constraints. However, an evolutionary perspective suggests that psychological safeguards should also protect individuals prior to catastrophic hyperthermia, and exposure to hot environments or elevated body temperature may directly attenuate central drive for exercise even well before the attainment of a critical limiting central temperature. Voluntary exercise tolerance or pacing may be influenced by a complex integration of peripheral and central thermal afferents, with regional differences in thermosensitivity across the skin surface and individual variability due to age and fitness. Despite the risk of accidents from impairments in mental function, heat exposure guidelines are commonly driven by physiological parameters, and the incorporation of a psychological component should be an important focus in occupational health and safety. In directly counteracting the effects of heat stress, the face and head is a region of high sudomotor and thermal sensitivity, and may thereby serve as an effective site for reducing perceptual and/or physiological heat strain via improvements in ventilation, airflow, or active cooling.
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Affiliation(s)
- Stephen S Cheung
- Environmental Ergonomics Laboratory, School of Health and Human Performance, Dalhousie University, 6230 South Street, Halifax, NS, Canada.
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Cotter JD, Taylor NAS. The distribution of cutaneous sudomotor and alliesthesial thermosensitivity in mildly heat-stressed humans: an open-loop approach. J Physiol 2005; 565:335-45. [PMID: 15760945 PMCID: PMC1464483 DOI: 10.1113/jphysiol.2004.081562] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2004] [Accepted: 03/07/2005] [Indexed: 11/08/2022] Open
Abstract
The distribution of cutaneous thermosensitivity has not been determined in humans for the control of autonomic or behavioural thermoregulation under open-loop conditions. We therefore examined local cutaneous warm and cool sensitivities for sweating and whole-body thermal discomfort (as a measure of alliesthesia). Thirteen males rested supine during warming (+4 degrees C), and mild (-4 degrees C) and moderate (-11 degrees C) cooling of ten skin sites (274 cm2), whilst the core and remaining skin temperatures were clamped above the sweat threshold using a water-perfusion suit and climate chamber. Local thermosensitivities were calculated from changes in sweat rates (pooled from sweat capsules on all limbs) and thermal discomfort, relative to the changes in local skin temperature. Thermosensitivities were examined across local sites and body segments (e.g. torso, limbs). The face displayed stronger cold (-11 degrees C) sensitivity than the forearm, thigh, leg and foot (P = 0.01), and was 2-5 times more thermosensitive than any other segment for both sudomotor and discomfort responses (P = 0.01). The face also showed greater warmth sensitivity than the limbs for sudomotor control and discomfort (P = 0.01). The limb extremities ranked as the least thermosensitive segment for both responses during warming, and for discomfort responses during moderate cooling (-11 degrees C). Approximately 70% of the local variance in sudomotor sensitivity was common to the alliesthesial sensitivity. We believe these open-loop methods have provided the first clear evidence for a greater facial thermosensitivity for sweating and whole-body thermal discomfort.
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Affiliation(s)
- James D Cotter
- Department of Biomedical Science, University of Wollongong, NSW, Australia.
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Patterson MJ, Cotter JD, Taylor NA. Human sudomotor responses to heating and cooling upper-body skin surfaces: cutaneous thermal sensitivity. ACTA PHYSIOLOGICA SCANDINAVICA 1998; 163:289-96. [PMID: 9715741 DOI: 10.1046/j.1365-201x.1998.00379.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The influence of local skin temperature (Tskl) on the control of local and whole-body sweating was evaluated in eight healthy males. A water-perfusion garment (37 degrees C) and a climatic chamber (36.45 +/- 0.78 degrees C; [+/- SD]; relative humidity 60.3 +/- 1.6%) were used to raise and clamp skin and core temperatures. Warm and cool stimuli were applied to four upper-body skin regions (face, arm, forearm, hand) using perfusion patches (249.0 +/- 0.2 cm2). Heating elevated, while cooling suppressed sweat rate (msw) locally, and at other skin surfaces. However, the tendency for Tskl manipulations to induce localized sweat responses was no more powerful than it was at stimulating sweating in non-treated regions (P > 0.05). Accordingly, neither thermal stimulus produced significantly greater local sudomotor influences than were elicited contralaterally (P > 0.05). No statistical support was found for the notion of inter-regional differences in upper-body cutaneous thermal sensitivity for sudomotor control, and, regardless of the stimulation site, whole-body sudomotor responses to localized thermal treatments were equivalent (P > 0.05).
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Affiliation(s)
- M J Patterson
- Department of Biomedical Science, University of Wollongong, NSW, Australia
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Bothorel B, Galeou M, Dewasmes G, Hoeft A, Candas V. Leg skin temperature and thigh sweat output: possible central influence of local thermal inputs. EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY 1991; 62:405-9. [PMID: 1893903 DOI: 10.1007/bf00626611] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
To demonstrate whether or not the skin temperature of one lower limb can have an influence on the sweat rate of the contralateral leg, the two legs of five subjects were exposed inside leg-chambers to specific local thermal conditions while sweat rates were measured on both limbs. Three experiments (C I, II, III) of 3 h were carried out: each included two phases A and B. During A, the right leg was not ventilated, while the left leg was (C I) or was not (C II-III) ventilated. During B, the legs were either removed from the leg-chambers (C I) or ventilated inside the chambers at differently controlled levels of leg skin temperature (C II-III). At all times, sweat capsules on both legs measured the sweat rates of local areas of the thigh which were also temperature-controlled. Results showed that, at constant or slightly increased mean skin and core temperatures, the sweat output of one leg could be decreased at constant (C II) or higher local skin temperature (C III) probably due to a decrease in the temperature of the opposite leg. This finding is interpreted as a consequence of a central negative effect, originating from contralateral thermal inputs.
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Affiliation(s)
- B Bothorel
- CNRS-INRS, Laboratoire de Physiologie et de Psychologie Environmentales, Strasbourg, France
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