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Barwood MJ, Eglin C, Hills SP, Johnston N, Massey H, McMorris T, Tipton MJ, Wakabayashi H, Webster L. Habituation of the cold shock response: A systematic review and meta-analysis. J Therm Biol 2024; 119:103775. [PMID: 38211547 DOI: 10.1016/j.jtherbio.2023.103775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/27/2023] [Accepted: 12/01/2023] [Indexed: 01/13/2024]
Abstract
Cold water immersion (CWI) evokes the life-threatening reflex cold shock response (CSR), inducing hyperventilation, increasing cardiac arrhythmias, and increasing drowning risk by impairing safety behaviour. Repeated CWI induces CSR habituation (i.e., diminishing response with same stimulus magnitude) after ∼4 immersions, with variation between studies. We quantified the magnitude and coefficient of variation (CoV) in the CSR in a systematic review and meta-analysis with search terms entered to Medline, SportDiscus, PsychINFO, Pubmed, and Cochrane Central Register. Random effects meta-analyses, including effect sizes (Cohen's d) from 17 eligible groups (k), were conducted for heart rate (HR, n = 145, k = 17), respiratory frequency (fR, n = 73, k = 12), minute ventilation (Ve, n = 106, k = 10) and tidal volume (Vt, n = 46, k=6). All CSR variables habituated (p < 0.001) with large or moderate pooled effect sizes: ΔHR -14 (10) bt. min-1 (d: -1.19); ΔfR -8 (7) br. min-1 (d: -0.78); ΔVe, -21.3 (9.8) L. min-1 (d: -1.64); ΔVt -0.4 (0.3) L -1. Variation was greatest in Ve (control vs comparator immersion: 32.5&24.7%) compared to Vt (11.8&12.1%). Repeated CWI induces CSR habituation potentially reducing drowning risk. We consider the neurophysiological and behavioural consequences.
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Affiliation(s)
- Martin J Barwood
- Faculty of Social and Health Sciences, Leeds Trinity University, Horsforth, UK.
| | - Clare Eglin
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, UK
| | - Samuel P Hills
- Faculty of Health and Social Sciences, Bournemouth University, Bournemouth, UK
| | - Nicola Johnston
- Faculty of Social and Health Sciences, Leeds Trinity University, Horsforth, UK
| | - Heather Massey
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, UK
| | - Terry McMorris
- Department of Sport and Exercise Science, Institute for Sport, University of Chichester, College Lane, Chichester, West Sussex, UK
| | - Michael J Tipton
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, UK
| | - Hitoshi Wakabayashi
- Laboratory of Environmental Ergonomics, Faculty of Engineering, Hokkaido University, Sapporo, Japan
| | - Lisa Webster
- Faculty of Social and Health Sciences, Leeds Trinity University, Horsforth, UK
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Wright J, Massey H, Hollis S, Vale T, Bennett DLH, Maley M, Montgomery H, Tipton M, Eglin C. Peripheral sensory function in non-freezing cold injury patients and matched controls. Exp Physiol 2023; 108:438-447. [PMID: 36807948 PMCID: PMC10988457 DOI: 10.1113/ep090720] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 12/20/2022] [Indexed: 02/22/2023]
Abstract
NEW FINDINGS What is the central question of this study? Is peripheral sensory function impaired in the chronic phase of non-freezing cold injury (NFCI)? What is the main finding and its importance? Warm and mechanical detection thresholds are elevated and intraepidermal nerve fibre density is reduced in individuals with NFCI in their feet when compared to matched controls. This indicates impaired sensory function in individuals with NFCI. Interindividual variation was observed in all groups, and therefore a diagnostic cut-off for NFCI has yet to be established. Longitudinal studies are required to follow NFCI progression from formation to resolution ABSTRACT: The aim of this study was to compare peripheral sensory neural function of individuals with non-freezing cold injury (NFCI) with matched controls (without NFCI) with either similar (COLD) or minimal previous cold exposure (CON). Thirteen individuals with chronic NFCI in their feet were matched with the control groups for sex, age, race, fitness, body mass index and foot volume. All undertook quantitative sensory testing (QST) on the foot. Intraepidermal nerve fibre density (IENFD) was assessed 10 cm above the lateral malleolus in nine NFCI and 12 COLD participants. Warm detection threshold was higher at the great toe in NFCI than COLD (NFCI 45.93 (4.71)°C vs. COLD 43.44 (2.72)°C, P = 0.046), but was non-significantly different from CON (CON 43.92 (5.01)°C, P = 0.295). Mechanical detection threshold on the dorsum of the foot was higher in NFCI (23.61 (33.59) mN) than in CON (3.83 (3.69) mN, P = 0.003), but was non-significantly different from COLD (10.49 (5.76) mN, P > 0.999). Remaining QST measures did not differ significantly between groups. IENFD was lower in NFCI than COLD (NFCI 8.47 (2.36) fibre/mm2 vs. COLD 11.93 (4.04) fibre/mm2 , P = 0.020). Elevated warm and mechanical detection thresholds may indicate hyposensitivity to sensory stimuli in the injured foot for individuals with NFCI and may be due to reduced innervation given the reduction in IENFD. Longitudinal studies are required to identify the progression of sensory neuropathy from the formation of injury to its resolution, with appropriate control groups employed.
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Affiliation(s)
- Jennifer Wright
- Extreme Environments Laboratory, School of Sport, Health and Exercise ScienceUniversity of PortsmouthPortsmouthUK
| | - Heather Massey
- Extreme Environments Laboratory, School of Sport, Health and Exercise ScienceUniversity of PortsmouthPortsmouthUK
| | - Sarah Hollis
- Regional Occupational Health Team (ROHT) CatterickCatterick GarrisonUK
| | - Tom Vale
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordUK
| | | | - Matthew Maley
- Environmental Ergonomics Research Centre, Loughborough School of Design and Creative ArtsLoughborough UniversityLoughboroughUK
| | | | - Michael Tipton
- Extreme Environments Laboratory, School of Sport, Health and Exercise ScienceUniversity of PortsmouthPortsmouthUK
| | - Clare Eglin
- Extreme Environments Laboratory, School of Sport, Health and Exercise ScienceUniversity of PortsmouthPortsmouthUK
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Tipton M, Eglin C. Non-freezing cold injury: A little-known big problem. Exp Physiol 2023; 108:329-330. [PMID: 36807674 PMCID: PMC10103876 DOI: 10.1113/ep091139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 01/31/2023] [Indexed: 02/22/2023]
Affiliation(s)
- Mike Tipton
- Extreme Environments LaboratorySHES, University of PortsmouthPortsmouthEngland
| | - Clare Eglin
- Extreme Environments LaboratorySHES, University of PortsmouthPortsmouthEngland
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Wilkes M, Long G, Massey H, Eglin C, Tipton M. Quantifying Risk in Air Sports: Flying Activity and Incident Rates in Paragliding. Wilderness Environ Med 2022; 33:66-74. [DOI: 10.1016/j.wem.2021.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 11/19/2021] [Accepted: 11/19/2021] [Indexed: 11/26/2022]
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Wilkes M, Long G, Charles R, Massey H, Eglin C, Tipton MJ. Paraglider Reserve Parachute Deployment Under Radial Acceleration. Aerosp Med Hum Perform 2021; 92:579-587. [PMID: 34503632 DOI: 10.3357/amhp.5854.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
INTRODUCTION: The paragliding reserve parachute system is safety-critical but underused, unstandardized, and known to fail. This study aimed to characterize reserve parachute deployment under radial acceleration to make recommendations for system design and paraglider pilot training.METHODS: There were 88 licensed amateur paraglider pilots who were filmed deploying their reserve parachutes from a centrifuge. Of those, 43 traveled forward at 4 G simulating a spiral dive, and 45 traveled backward at 3 G simulating a rotational maneuver known as SAT. Tests incorporated ecologically valid body, hand, and gaze positions, and cognitive loading and switching akin to real deployment. The footage was reviewed by subject matter experts and compared to previous work in linear acceleration.RESULTS: Of the pilots, 2.3 failed to extract the reserve container from the harness. SAT appeared more cognitively demanding than spiral, despite lower G. Participants located the reserve handle by touch not sight. The direction of travel influenced their initial contact with the harness: 82.9 searched first on their hip in spiral, 63.4 searched first on their thigh in SAT. Search patterns followed skeletal landmarks. Participants had little directional control over their throw.CONCLUSIONS: Paraglider pilots are part of the reserve system. Maladaptive behaviors observed under stress highlighted that components must work in harmony with pilots natural responses, with minimal cognitive demands or need for innovation or problem-solving. Recommendations include positioning prominent, tactile reserve handles overlying the pilots hip; deployment bags extractable with any angle of pull; deployment in a single sweeping backward action; and significantly increasing reserve deployment drills.Wilkes M, Long G, Charles R, Massey H, Eglin C, Tipton MJ. Paraglider reserve parachute deployment under radial acceleration. Aerosp Med Hum Perform. 2021; 92(7):579587.
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James TJ, Corbett J, Cummings M, Allard S, Young JS, Towse J, Carey-Jones K, Eglin C, Hopkins B, Morgan C, Tipton M, Saynor ZL, Shepherd AI. Timing of acute passive heating on glucose tolerance and blood pressure in people with type 2 diabetes: a randomized, balanced crossover, control trial. J Appl Physiol (1985) 2021; 130:1093-1105. [PMID: 33411640 DOI: 10.1152/japplphysiol.00747.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is characterized by chronic hyperglycemia and progressive insulin resistance, leading to macro and microvascular dysfunction. Passive heating has potential to improve glucose homeostasis and act as an exercise mimetic. We assessed the effect of acute passive heating before or during an oral glucose tolerance test (OGTT) in people with T2DM. Twelve people with T2DM were randomly assigned to the following three conditions: 1) 3-h OGTT (control), 2) 1-h passive heating (40°C water) 30 min before an OGTT (HOT-OGTT), and 3) 1-h passive heating (40°C water) 30 min after commencing an OGTT (OGTT-HOT). Blood glucose concentration, insulin sensitivity, extracellular heat shock protein 70 (eHSP70), total energy expenditure (TEE), heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were recorded. Passive heating did not alter blood glucose concentration [control: 1,677 (386) arbitrary units (AU), HOT-OGTT: 1,797 (340) AU, and OGTT-HOT: 1,662 (364) AU, P = 0.28], insulin sensitivity (P = 0.15), or SBP (P = 0.18) but did increase eHSP70 concentration in both heating conditions [control: 203.48 (110.81) pg·mL-1; HOT-OGTT: 402.47 (79.02) pg·mL-1; and OGTT-HOT: 310.00 (60.53) pg·mL-1, P < 0.001], increased TEE (via fat oxidation) in the OGTT-HOT condition [control: 263 (33) kcal, HOT-OGTT: 278 (40) kcal, and OGTT-HOT: 304 (38) kcal, P = 0.001], increased HR in both heating conditions (P < 0.001), and reduced DBP in the OGTT-HOT condition (P < 0.01). Passive heating in close proximity to a glucose challenge does not alter glucose tolerance but does increase eHSP70 concentration and TEE and reduce blood pressure in people with T2DM.NEW & NOTEWORTHY This is the first study to investigate the timing of acute passive heating on glucose tolerance and extracellular heat shock protein 70 concentration ([eHSP70]) in people with type 2 diabetes. The principal novel findings from this study were that both passive heating conditions: 1) did not reduce the area under the curve or peak blood glucose concentration, 2) elevated heart rate, and 3) increased [eHSP70], which was blunted by glucose ingestion, while passive heating following glucose ingestion, 4) increased total energy expenditure, and 5) reduced diastolic blood pressure.
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Affiliation(s)
- Thomas J James
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom.,Diabetes and Endocrinology Department, Portsmouth Hospitals University NHS Trust, Portsmouth, United Kingdom
| | - Jo Corbett
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Michael Cummings
- Diabetes and Endocrinology Department, Portsmouth Hospitals University NHS Trust, Portsmouth, United Kingdom
| | - Sharon Allard
- Diabetes and Endocrinology Department, Portsmouth Hospitals University NHS Trust, Portsmouth, United Kingdom
| | - John S Young
- School of Pharmacy and Biomedical Sciences, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Jonathan Towse
- School of Pharmacy and Biomedical Sciences, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Kathryn Carey-Jones
- School of Biological Sciences, Faculty of Science and Health, University of Portsmouth, United Kingdom.,Oaks Healthcare, Cowplain Family Practice, Waterlooville, United Kingdom
| | - Clare Eglin
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Billy Hopkins
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Connor Morgan
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Michael Tipton
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Zoe L Saynor
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom.,Diabetes and Endocrinology Department, Portsmouth Hospitals University NHS Trust, Portsmouth, United Kingdom
| | - Anthony I Shepherd
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom.,Diabetes and Endocrinology Department, Portsmouth Hospitals University NHS Trust, Portsmouth, United Kingdom
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Wilkes M, Charles R, Long G, Massey H, Eglin C, Tipton M. Ergonomics of paragliding reserve parachute deployment in linear acceleration. Appl Ergon 2021; 90:103229. [PMID: 32882502 DOI: 10.1016/j.apergo.2020.103229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 06/14/2020] [Accepted: 07/26/2020] [Indexed: 06/11/2023]
Affiliation(s)
- Matt Wilkes
- Extreme Environments Laboratory, Department of Sports and Exercise Science, Spinnaker Building, University of Portsmouth, 2 Cambridge Road, Portsmouth, Hampshire PO1 2ER, United Kingdom.
| | - Rebecca Charles
- Rail Safety and Standards Board, The Helicon, 1 South Place, London EC2M 2RB, United Kingdom
| | - Geoff Long
- Extreme Environments Laboratory, Department of Sports and Exercise Science, Spinnaker Building, University of Portsmouth, 2 Cambridge Road, Portsmouth, Hampshire PO1 2ER, United Kingdom
| | - Heather Massey
- Extreme Environments Laboratory, Department of Sports and Exercise Science, Spinnaker Building, University of Portsmouth, 2 Cambridge Road, Portsmouth, Hampshire PO1 2ER, United Kingdom
| | - Clare Eglin
- Extreme Environments Laboratory, Department of Sports and Exercise Science, Spinnaker Building, University of Portsmouth, 2 Cambridge Road, Portsmouth, Hampshire PO1 2ER, United Kingdom
| | - Michael Tipton
- Extreme Environments Laboratory, Department of Sports and Exercise Science, Spinnaker Building, University of Portsmouth, 2 Cambridge Road, Portsmouth, Hampshire PO1 2ER, United Kingdom
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Abstract
INTRODUCTION: Paragliding is an emerging discipline of aviation, with recreational pilots flying distances over 100 km. It remains risky. Accidents typically relate to pilot error rather than equipment failure. We measured cognition and physiological responses during simulated flight, to investigate whether errors might be due to pilot impairment, rather than misjudgment.METHODS: There were 10 male paraglider pilots (aged 19-58 yr) who undertook a simulated flight in an environmental chamber from sea level (0.209 FIo₂) to 1524 m (0.174 FIo₂), 2438 m (0.156 FIo₂), and 3658 m (0.133 FIo₂), over approximately 2 h. They experienced normobaric hypoxia, environmental cooling and headwind, completing logical reasoning, mannikin, mathematical processing, Stroop Color-Word and Tower Puzzle tasks; as well as measures of risk-taking (BART), mood (POMS), and subjective experience.RESULTS: Results were compared to ten controls, matched by age, sex, and flying experience. Physiological measures were oxygen consumption, carbon dioxide production, ventilation, heart rate, oxygen saturation, rectal and skin temperatures, blood glucose, blood lactate, and urine production. There were no significant differences between pilots and controls at any altitude. Results were heterogenous within and between individuals. As altitude increased, oxygen consumption and minute volume increased significantly, while oxygen saturations fell (98.3% [baseline] to 88.5% [peak]). Rectal temperatures fell by a statistically (but not clinically) significant amount (37.6°C to 37.3°C), while finger skin temperatures dropped steeply (32.2°C to 13.9°C).DISCUSSION: Results suggest cognitive impairment is unlikely to be a primary cause of pilot error during paragliding flights (of less than 2 h, below 3658 m), though hand protection requires improvement.Wilkes M, Long G, Massey H, Eglin C, Tipton MJ. Cognitive function in simulated paragliding flight. Aerosp Med Hum Perform. 2019; 90(10):851-859.
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Wilkes M, MacInnis MJ, Hawkes LA, Massey H, Eglin C, Tipton MJ. The Physiology of Paragliding Flight at Moderate and Extreme Altitudes. High Alt Med Biol 2017; 19:42-51. [PMID: 29265914 DOI: 10.1089/ham.2017.0127] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Wilkes, Matt, Martin J. MacInnis, Lucy A. Hawkes, Heather Massey, Clare Eglin, and Michael J. Tipton. The physiology of paragliding flight at moderate and extreme altitudes. High Alt Med Biol 19:42-51, 2018.-Paragliding is a form of free flight, with extreme-altitude paragliding being an emerging discipline. We aimed to describe the physiological demands and the impact of environmental stressors of paragliding at moderate and extreme altitudes. We recorded oxygen consumption (VO2), heart rate (HR), respiratory frequency (fR), tidal volume (VT), oxygen saturation, accelerometry (G), and altitude in 9.3 hours of flight at moderate altitudes (to 3073 m, n = 4), 19.3 hours at extreme altitude (to 7458 m, n = 2), and during high-G maneuvers (n = 2). We also analyzed HR data from an additional 17 pilots (138 hours) using the Flymaster Live database to corroborate our findings. All pilots were male. Overall energy expenditure at moderate altitude was low [1.7 (0.6) metabolic equivalents], but physiological parameters were notably higher during takeoff (p < 0.05). Pilots transiently reached ∼7 G during maneuvers. Mean HR at extreme altitude [112 (14) bpm] was elevated compared to moderate altitude [98 (15) bpm, p = 0.048]. Differences in pilots' VT and fR at moderate and extreme altitudes were not statistically significant (p = 0.96 and p = 0.058, respectively). Thus, we conclude that physical exertion in paragliding is low, suggesting that any subjective fatigue felt by pilots is likely to be cognitive or environmental. Future research should focus on reducing mental workload, enhancing cognitive function, and improving environmental protection.
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Affiliation(s)
- Matt Wilkes
- 1 Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth , Portsmouth, United Kingdom
| | | | - Lucy A Hawkes
- 3 College of Life and Environmental Sciences, University of Exeter , Exeter, United Kingdom
| | - Heather Massey
- 1 Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth , Portsmouth, United Kingdom
| | - Clare Eglin
- 1 Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth , Portsmouth, United Kingdom
| | - Michael J Tipton
- 1 Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth , Portsmouth, United Kingdom
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Moreira DG, Costello JT, Brito CJ, Adamczyk JG, Ammer K, Bach AJ, Costa CM, Eglin C, Fernandes AA, Fernández-Cuevas I, Ferreira JJ, Formenti D, Fournet D, Havenith G, Howell K, Jung A, Kenny GP, Kolosovas-Machuca ES, Maley MJ, Merla A, Pascoe DD, Priego Quesada JI, Schwartz RG, Seixas AR, Selfe J, Vainer BG, Sillero-Quintana M. Thermographic imaging in sports and exercise medicine: A Delphi study and consensus statement on the measurement of human skin temperature. J Therm Biol 2017; 69:155-162. [DOI: 10.1016/j.jtherbio.2017.07.006] [Citation(s) in RCA: 153] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 06/27/2017] [Accepted: 07/17/2017] [Indexed: 11/28/2022]
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Hope K, Eglin C, Golden F, Tipton M. Sublingual glyceryl trinitrate and the peripheral thermal responses in normal and cold-sensitive individuals. Microvasc Res 2013; 91:84-9. [PMID: 24280630 DOI: 10.1016/j.mvr.2013.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Revised: 11/13/2013] [Accepted: 11/15/2013] [Indexed: 11/15/2022]
Abstract
Non-freezing cold injury (NFCI) is a prevalent, but largely undiagnosed and poorly understood syndrome afflicting many who, as part of their work or leisure, expose their extremities to cold temperatures. The long term sequelae of NFCI are hyperhidrosis, cold-sensitivity and pain; these can last a lifetime. We tested the hypothesis that, in comparison with a placebo, sublingual glyceryl trinitrate (GTN) would increase the peripheral microcirculation during and after a mild cold challenge of individuals who had not been diagnosed with NFCI, but were cold-sensitive. Naive participants were categorised into two cohort groups: control (n=7) or cold-sensitive (n=6). All participants undertook a standardised two minute cold exposure of their right foot while toe skin temperature (Tsk; infra-red thermograms) and blood flow (toe pad laser Doppler) were measured. GTN increased the rate of rewarming and absolute Tsk of the coldest toe after the cold challenge in cold-sensitive individuals. GTN also increased the blood flow in the great toe during rewarming in some cold-sensitive individuals. We accept our hypothesis and suggest that the impairment in the vasodilatory response seen in individuals with cold-sensitivity can be overcome by the use of GTN, an endothelial-independent NO donor, and thereby improve the rewarming of cooled peripheral tissues.
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Affiliation(s)
- Katrina Hope
- Department of Anaesthesia, Bristol Royal Infirmary, Upper Maudlin Street, Bristol BS2 8HW, UK
| | - Clare Eglin
- Extreme Environments Laboratory, Department of Sport & Exercise Science, University of Portsmouth, Spinnaker Building, Cambridge Road, Portsmouth PO1 2ER, UK
| | - Frank Golden
- Extreme Environments Laboratory, Department of Sport & Exercise Science, University of Portsmouth, Spinnaker Building, Cambridge Road, Portsmouth PO1 2ER, UK
| | - Mike Tipton
- Extreme Environments Laboratory, Department of Sport & Exercise Science, University of Portsmouth, Spinnaker Building, Cambridge Road, Portsmouth PO1 2ER, UK.
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Robson-Ansley P, Barwood M, Canavan J, Hack S, Eglin C, Davey S, Hewitt J, Hull J, Ansley L. The effect of repeated endurance exercise on IL-6 and sIL-6R and their relationship with sensations of fatigue at rest. Cytokine 2009; 45:111-6. [DOI: 10.1016/j.cyto.2008.11.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 11/04/2008] [Accepted: 11/06/2008] [Indexed: 11/15/2022]
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Abstract
The present study examined the ability of the crew of small fast rescue boats to perform basic life support (BLS) at sea. Tests were undertaken aboard a 67m emergency response and rescue vessel (ERRV), a 9.1m (30ft) and 11.6m (38ft) fast rescue craft ("daughter craft" (DC)). It was hypothesised that the ability to perform BLS on a DC would be significantly impaired when compared with that seen on the ERRV. Nine DC crew volunteered for the study. These tests were undertaken in sea states ranging from 0.5 to 6 (13cm to 4m wave height). Wind speeds ranged between 0 and 35knots. The deterioration observed in the performance of BLS on board the DC compared to that seen on the ERRV was significant (P<0.05) and was due, in part, to a tendency to over-inflate during rescue breathing, and under-compress during BLS when on the DC. Chest compression (CC) was impaired significantly above a sea state 3 (wave height 61-92cm). It is concluded that the performance of BLS on small boats, in particular rescue breathing, is significantly adversely affected by two major factors, motion-induced interruption and early fatigue. As a consequence, the likelihood of conducting fully effective continuous BLS on a small boat in a seaway for any length of time, with a good chance of a successful outcome, is considered to be poor. However, this should not deter rescuers from attempting to make such efforts where practicable.
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Affiliation(s)
- M Tipton
- Institute of Biomedical & Biomolecular Sciences, Department of Sport & Exercise Science, University of Portsmouth, UK.
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Abstract
BACKGROUND General hypothermia (deep body temperature <35 degrees C) has been implicated in immersion-related deaths, but many deaths occur too quickly for it to be involved. We investigated changes in swimming capability in cold water to find out whether such changes could lead to swim failure and drowning. METHODS Ten volunteers undertook three self-paced breaststroke swims in a variable-speed swimming flume, in water at 25 degrees C, 18 degrees C, and 10 degrees C, for a maximum of 90 min. During each swim, we measured oxygen consumption, rectal temperature, swim speed and angle, and stroke rate and length. Swim failure was defined as being unable to keep feet off the bottom of the flume. FINDINGS All ten swimmers completed 90 min swims at 25 degrees C, eight completed swims at 18 degrees C, and five at 10 degrees C. In 10 degrees C water, one swimmer reached swim failure after 61 min and four were withdrawn before 90 min with rectal temperatures of 35 degrees C when they were close to swim failure. Swimming efficiency and length of stroke decreased more and rate of stroke and swim angle increased more in 10 degrees C water than in warmer water. These variables seemed to characterise impending swim failure. INTERPRETATION Impaired performance and initial cardiorespiratory responses to immersion probably represent the major dangers to immersion victims. Consequently, treatment should be aimed at symptoms resulting from near-drowning rather than severe hypothermia.
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Affiliation(s)
- M Tipton
- Department of Sport and Exercise Science, University of Portsmouth, UK.
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