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Morrissey-Basler MC, Brewer GJ, Anderson T, Adams WM, Navarro JS, Marcelino M, Martin DG, Casa DJ. The effect of heat mitigation strategies on thermoregulation and productivity during simulated occupational work in the heat in physically active young men. Front Sports Act Living 2024; 5:1274141. [PMID: 38274034 PMCID: PMC10808760 DOI: 10.3389/fspor.2023.1274141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 12/26/2023] [Indexed: 01/27/2024] Open
Abstract
Purpose To investigate heat stress mitigation strategies on productivity and thermoregulatory responses during simulated occupational work in the heat. Methods Thirteen physically active men (age, 25 ± 4 years; body mass,77.8 ± 14.7 kg; VO2peak, 44.5 ± 9.2 ml·kg-1·min-1) completed five randomized-controlled trials in a hot environment (40°C, 40% relative humidity). Each trial was 4.5 h in duration to simulate an outdoor occupational shift. Thermoregulatory responses (heart rate, HR; rectal temperature, Trec; mean skin temperature, Tsk), perceptual responses (rating of perceived exertion, RPE; thermal sensation; thermal comfort; fatigue) and productivity outcomes (box lifting repetitions, time to exhaustion) were examined in the following heat mitigation strategy interventions: (1) simulated solar radiation with limited fluid intake [SUN]; (2) simulated solar radiation with no fluid restrictions [SUN + H2O]; (3) shade (no simulated solar radiation during trial) with no fluid restrictions [SHADE + H2O]; (4) shade and cooling towels during rest breaks with no fluid restrictions [COOL + H2O]; and (5) shade with cooling towels, cooling vest during activity with no fluid restrictions [COOL + VEST + H2O]. Results [COOL + VEST + H2O] had lower Trec compared to [SUN] [p = 0.004, effect size(ES) = 1.48], [SUN + H2O] (p < 0.001, ES = -1.87), and [SHADE + H2O] (p = 0.001, ES = 1.62). Average Tsk was lower during the treadmill and box lifting activities in the [COOL + VEST + H2O] compared to [SUN] (p < 0.001, ES = 7.92), [SUN + H2O] (p < 0.001,7.96), [SHADE + H2O] (p < 0.001), and [COOL + H2O] (p < 0.001, ES = 3.01). There were performance differences during the [COOL + VEST + H2O] (p = 0.033) and [COOL + H2O] (p = 0.023) conditions compared to [SUN] during phases of the experimental trial, however, there were no differences in total box lifting repetitions between trials (p > 0.05). Conclusion Our results suggest that during a simulated occupational shift in a laboratory setting, additional heat mitigation strategies ([COOL + VEST + H2O] and [COOL + H2O]) reduced physiological strain and improved box lifting performance to a greater degree than [SUN]. These differences may have been attributed to a larger core to skin temperature gradient or reduction in fatigue, thermal sensation, and RPE during [COOL + H2O] and [COOL + VEST + H2O]. These data suggest that body cooling, hydration, and "shade" (removal of simulated radiant heat) as heat stress mitigation strategies should be considered as it reduces physiological strain while producing no additional harm.
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Affiliation(s)
- Margaret C. Morrissey-Basler
- Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Storrs, CT, United States
- Department of Health Sciences, Providence College, Providence, RI, United States
| | - Gabrielle J. Brewer
- Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Storrs, CT, United States
| | - Travis Anderson
- Department of Sports Medicine, UnitedStates Olympic & Paralympic Committee, Colorado Springs, CO, United States
- UnitedStates Coalition for the Prevention of Illness and Injury in Sport, Colorado Springs, CO, United States
| | - William M. Adams
- Department of Sports Medicine, UnitedStates Olympic & Paralympic Committee, Colorado Springs, CO, United States
- UnitedStates Coalition for the Prevention of Illness and Injury in Sport, Colorado Springs, CO, United States
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom
- Department of Kinesiology, University of North Carolina at Greensboro, Greensboro, NC, United States
| | - John S. Navarro
- Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Storrs, CT, United States
| | - Monique Marcelino
- Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Storrs, CT, United States
| | - David G. Martin
- Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Storrs, CT, United States
| | - Douglas J. Casa
- Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Storrs, CT, United States
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Brearley M, Berry R, Hunt AP, Pope R. A Systematic Review of Post-Work Core Temperature Cooling Rates Conferred by Passive Rest. BIOLOGY 2023; 12:biology12050695. [PMID: 37237510 DOI: 10.3390/biology12050695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/04/2023] [Accepted: 05/05/2023] [Indexed: 05/28/2023]
Abstract
Physical work increases energy expenditure, requiring a considerable elevation of metabolic rate, which causes body heat production that can cause heat stress, heat strain, and hyperthermia in the absence of adequate cooling. Given that passive rest is often used for cooling, a systematic search of literature databases was conducted to identify studies that reported post-work core temperature cooling rates conferred by passive rest, across a range of environmental conditions. Data regarding cooling rates and environmental conditions were extracted, and the validity of key measures was assessed for each study. Forty-four eligible studies were included, providing 50 datasets. Eight datasets indicated a stable or rising core temperature in participants (range 0.000 to +0.028 °C min-1), and forty-two datasets reported reducing core temperature (-0.002 to -0.070 °C min-1) during passive rest, across a range of Wet-Bulb Globe Temperatures (WBGT). For 13 datasets where occupational or similarly insulative clothing was worn, passive rest resulted in a mean core temperature decrease of -0.004 °C min-1 (-0.032 to +0.013 °C min-1). These findings indicate passive rest does not reverse the elevated core temperatures of heat-exposed workers in a timely manner. Climate projections of higher WBGT are anticipated to further marginalise the passive rest cooling rates of heat-exposed workers, particularly when undertaken in occupational attire.
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Affiliation(s)
- Matt Brearley
- Thermal Hyperformance, Hervey Bay, QLD 4655, Australia
- National Critical Care and Trauma Response Centre, Darwin, NT 0800, Australia
- School of Allied Health, Exercise & Sports Sciences, Charles Sturt University, Albury, NSW 2640, Australia
| | - Rachel Berry
- School of Biomedical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Andrew P Hunt
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia
| | - Rodney Pope
- School of Allied Health, Exercise & Sports Sciences, Charles Sturt University, Albury, NSW 2640, Australia
- Tactical Research Unit, Bond University, Robina, QLD 4229, Australia
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Miller KC, Amaria NY. Excellent Rectal Temperature Cooling Rates in the Polar Life Pod Consistent With Stationary Tubs. J Athl Train 2023; 58:244-251. [PMID: 35192711 PMCID: PMC10176839 DOI: 10.4085/1062-6050-0732.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Several tools exist to reduce rectal temperature (TREC) quickly for patients experiencing exertional heatstroke (EHS). Stationary tubs effectively treat EHS but are bulky and impractical in some situations. More portable cold-water immersion techniques, such as tarp-assisted cooling with oscillation, are gaining popularity because of their benefits (eg, less water needed, portability). The Polar Life Pod (PLP) may be another portable way to reduce TREC, but few researchers have examined its effectiveness. OBJECTIVES To determine whether the PLP and stationary tub reduced TREC at acceptable or ideal rates, whether TREC cooling rates differed by method, and how participants felt before, during, and after cooling. DESIGN Randomized crossover study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Thirteen individuals (8 men, 5 women; age = 21 ± 2 years, mass = 73.99 ± 11.24 kg, height = 176.2 ± 11.1 cm). INTERVENTION(S) Participants exercised in the heat until TREC was 39.5°C. They immersed themselves in either the PLP (202.7 ± 23.8 L, 3.2 ± 0.6°C) or a stationary tub (567.8 ± 7.6 L, 15.0 ± 0.1°C) until TREC was 38°C. Thermal sensation and environmental symptom questionnaire (ESQ) responses were recorded before, during, and after exercise and cooling. MAIN OUTCOME MEASURE(S) Rectal temperature cooling rates, thermal sensation, and ESQ responses. RESULTS Participants had similar exercise durations (PLP = 41.6 ± 6.9 minutes, tub = 42.2 ± 9.3 minutes, t12 = 0.5, P = .31), thermal sensation scores (PLP = 7.0 ± 0.5, tub = 7.0 ± 0.5, P > .05), and ESQ scores (PLP = 25 ± 13, tub = 29 ± 14, P > .05) immediately postexercise each day. Although TREC cooling rates were excellent in both conditions, the PLP cooled faster than the stationary tub (PLP = 0.28 ± 0.09°C/min, tub = 0.20 ± 0.09°C/min, t12 = 2.5, P = .01). Thermal sensation in the PLP condition was lower than that in the tub condition halfway through cooling (PLP = 1 ± 1, tub = 2 ± 1, P < .05) and postcooling (PLP = 2 ± 1, tub = 3 ± 1, P < .05). The ESQ scores were higher for PLP than for the stationary tub postcooling (PLP = 25 ± 14, tub = 12 ± 9, P < .05). CONCLUSIONS The PLP and the stationary tub cooled individuals with hyperthermia at ideal rates for treating patients with EHS (ie, >0.16°C/min). The PLP may be an effective tool for treating EHS when limited water volumes and portability are concerns. Clinicians should have rewarming tools and strategies (eg, heating blankets) available to improve patients' comfort after PLP use.
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Affiliation(s)
- Kevin C. Miller
- Department of Health and Human Performance, Texas State University, San Marcos
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Efficacy of two intermittent cooling strategies during prolonged work-rest intervals in the heat with personal protective gear compared with a control condition. Eur J Appl Physiol 2023; 123:1125-1134. [PMID: 36651993 DOI: 10.1007/s00421-023-05139-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 01/09/2023] [Indexed: 01/19/2023]
Abstract
INTRODUCTION Personal protective equipment (PPE) inhibits heat dissipation and elevates heat strain. Impaired cooling with PPE warrants investigation into practical strategies to improve work capacity and mitigate exertional heat illness. PURPOSE Examine physiological and subjective effects of forearm immersion (FC), fan mist (MC), and passive cooling (PC) following three intermittent treadmill bouts while wearing PPE. METHODS Twelve males (27 ± 6 years; 57.6 ± 6.2 ml/kg/min; 78.3 ± 8.1 kg; 183.1 ± 7.2 cm) performed three 50-min (10 min of 40%, 70%, 40%, 60%, 50% vVO2max) treadmill bouts in the heat (36 °C, 30% relative humidity). Thirty minutes of cooling followed each bout, using one of the three strategies per trial. Rectal temperature (Tcore), skin temperature (Tsk), heart rate (HR), heart rate recovery (HRR), rating of perceived exertion (RPE), thirst, thermal sensation (TS), and fatigue were obtained. Repeated-measures analysis of variance (condition x time) detected differences between interventions. RESULTS Final Tcore was similar between trials (P > .05). Cooling rates were larger in FC and MC vs PC following bout one (P < .05). HRR was greatest in FC following bouts two (P = .013) and three (P < .001). Tsk, fluid consumption, and sweat rate were similar between all trials (P > .05). TS and fatigue during bout three were lower in MC, despite similar Tcore and HR. CONCLUSION Utilizing FC and MC during intermittent work in the heat with PPE yields some thermoregulatory and cardiovascular benefit, but military health and safety personnel should explore new and novel strategies to mitigate risk and maximize performance under hot conditions while wearing PPE.
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Racinais S, Hosokawa Y, Akama T, Bermon S, Bigard X, Casa DJ, Grundstein A, Jay O, Massey A, Migliorini S, Mountjoy M, Nikolic N, Pitsiladis YP, Schobersberger W, Steinacker JM, Yamasawa F, Zideman DA, Engebretsen L, Budgett R. IOC consensus statement on recommendations and regulations for sport events in the heat. Br J Sports Med 2023; 57:8-25. [PMID: 36150754 PMCID: PMC9811094 DOI: 10.1136/bjsports-2022-105942] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2022] [Indexed: 01/07/2023]
Abstract
This document presents the recommendations developed by the IOC Medical and Scientific Commission and several international federations (IF) on the protection of athletes competing in the heat. It is based on a working group, meetings, field experience and a Delphi process. The first section presents recommendations for event organisers to monitor environmental conditions before and during an event; to provide sufficient ice, shading and cooling; and to work with the IF to remove regulatory and logistical limitations. The second section summarises recommendations that are directly associated with athletes' behaviours, which include the role and methods for heat acclimation; the management of hydration; and adaptation to the warm-up and clothing. The third section explains the specific medical management of exertional heat stroke (EHS) from the field of play triage to the prehospital management in a dedicated heat deck, complementing the usual medical services. The fourth section provides an example for developing an environmental heat risk analysis for sport competitions across all IFs. In summary, while EHS is one of the leading life-threatening conditions for athletes, it is preventable and treatable with the proper risk mitigation and medical response. The protection of athletes competing in the heat involves the close cooperation of the local organising committee, the national and international federations, the athletes and their entourages and the medical team.
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Affiliation(s)
- Sebastien Racinais
- Research and Scientific Support Department, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Ad Dawhah, Qatar
| | - Yuri Hosokawa
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
| | - Takao Akama
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
| | | | - Xavier Bigard
- Union Cycliste Internationale (UCI), Aigle, Switzerland
| | - Douglas J Casa
- Korey Stringer Institiute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut, USA
| | - Andrew Grundstein
- Department of Geography, University of Georgia, Athens, Georgia, USA
| | - Ollie Jay
- Heat and Health Research Incubator, Faculty of Medicine and Health, The University of Sydney, Camperdown, New South Wales, Australia
| | - Andrew Massey
- Medical Department, Federation Internationale de Football Association, Zurich, Switzerland
| | | | | | | | | | - Wolfgang Schobersberger
- Institute for Sports Medicine, Alpine Medicine & Health Tourism (ISAG), UMIT Tirol – Private University for Health Sciences and technology, Hall, Austria,University Hospital/Tirol Kliniken, Innsbruck, Austria
| | | | | | - David Anthony Zideman
- International Olympic Committee Medical and Scientific Games Group, Pinner, Middlesex, UK
| | - Lars Engebretsen
- Medical and Scientific Department, International Olympic Committee, Lausanne, Switzerland
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Wang G, Zhang T, Wang A, Hurr C. Topical Analgesic Containing Methyl Salicylate and L-Menthol Accelerates Heat Loss During Skin Cooling for Exercise-Induced Hyperthermia. Front Physiol 2022; 13:945969. [PMID: 35910580 PMCID: PMC9326359 DOI: 10.3389/fphys.2022.945969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/21/2022] [Indexed: 11/29/2022] Open
Abstract
Hyperthermia impairs physical performance and, when prolonged, results in heat stroke or other illnesses. While extensive research has investigated the effectiveness of various cooling strategies, including cold water immersion and ice-suit, there has been little work focused on overcoming the cutaneous vasoconstriction response to external cold stimulation, which can reduce the effectiveness of these treatments. Over-the-counter (OTC) topical analgesics have been utilized for the treatment of muscle pain for decades; however, to date no research has examined the possibility of taking advantage of their vasodilatory functions in the context of skin cooling. We tested whether an OTC analgesic cream containing 20% methyl salicylate and 6% L-menthol, known cutaneous vasodilators, applied to the skin during skin cooling accelerates heat loss in exercise-induced hyperthermia. Firstly, we found that cutaneous application of OTC topical analgesic cream can attenuate cold-induced vasoconstriction and enhance heat loss during local skin cooling. We also revealed that core body heat loss, as measured by an ingestible telemetry sensor, could be accelerated by cutaneous application of analgesic cream during ice-suit cooling in exercise-induced hyperthermia. A blunted blood pressure response was observed during cooling with the analgesic cream application. Given the safety profile and affordability of topical cutaneous analgesics containing vasodilatory agents, our results suggest that they can be an effective and practical tool for enhancing the cooling effects of skin cooling for hyperthermia.
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Affiliation(s)
- Gang Wang
- Integrative Exercise Physiology Laboratory, Department of Physical Education, Jeonbuk National University, Jeonju, South Korea
- Department of Physical Education, Xinyang Normal University, Xingang, China
| | - Tingran Zhang
- Integrative Exercise Physiology Laboratory, Department of Physical Education, Jeonbuk National University, Jeonju, South Korea
| | - Anjie Wang
- Integrative Exercise Physiology Laboratory, Department of Physical Education, Jeonbuk National University, Jeonju, South Korea
| | - Chansol Hurr
- Integrative Exercise Physiology Laboratory, Department of Physical Education, Jeonbuk National University, Jeonju, South Korea
- *Correspondence: Chansol Hurr,
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Morrissey MC, Casa DJ, Brewer GJ, Adams WM, Hosokawa Y, Benjamin CL, Grundstein AJ, Hostler D, McDermott BP, McQuerry ML, Stearns RL, Filep EM, DeGroot DW, Fulcher J, Flouris AD, Huggins RA, Jacklitsch BL, Jardine JF, Lopez RM, McCarthy RB, Pitisladis Y, Pryor RR, Schlader ZJ, Smith CJ, Smith DL, Spector JT, Vanos JK, Williams WJ, Vargas NT, Yeargin SW. Heat Safety in the Workplace: Modified Delphi Consensus to Establish Strategies and Resources to Protect the US Workers. GEOHEALTH 2021; 5:e2021GH000443. [PMID: 34471788 PMCID: PMC8388206 DOI: 10.1029/2021gh000443] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/08/2021] [Accepted: 06/11/2021] [Indexed: 06/04/2023]
Abstract
The purpose of this consensus document was to develop feasible, evidence-based occupational heat safety recommendations to protect the US workers that experience heat stress. Heat safety recommendations were created to protect worker health and to avoid productivity losses associated with occupational heat stress. Recommendations were tailored to be utilized by safety managers, industrial hygienists, and the employers who bear responsibility for implementing heat safety plans. An interdisciplinary roundtable comprised of 51 experts was assembled to create a narrative review summarizing current data and gaps in knowledge within eight heat safety topics: (a) heat hygiene, (b) hydration, (c) heat acclimatization, (d) environmental monitoring, (e) physiological monitoring, (f) body cooling, (g) textiles and personal protective gear, and (h) emergency action plan implementation. The consensus-based recommendations for each topic were created using the Delphi method and evaluated based on scientific evidence, feasibility, and clarity. The current document presents 40 occupational heat safety recommendations across all eight topics. Establishing these recommendations will help organizations and employers create effective heat safety plans for their workplaces, address factors that limit the implementation of heat safety best-practices and protect worker health and productivity.
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Affiliation(s)
- Margaret C. Morrissey
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - Douglas J. Casa
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - Gabrielle J. Brewer
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - William M. Adams
- Department of KinesiologyUniversity of North Carolina at GreensboroGreensboroNCUSA
| | - Yuri Hosokawa
- Faculty of Sports SciencesWaseda UniversitySaitamaJapan
| | | | | | - David Hostler
- Department of Exercise and Nutrition SciencesCenter for Research and Education in Special EnvironmentsBuffaloNYUSA
| | - Brendon P. McDermott
- Department of Health, Human Performance and RecreationUniversity of ArkansasFayettevilleARUSA
| | | | - Rebecca L. Stearns
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - Erica M. Filep
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - David W. DeGroot
- Fort Benning Heat CenterMartin Army Community HospitalFort BenningGAUSA
| | | | - Andreas D. Flouris
- Department of Exercise ScienceFAME LaboratoryUniversity of ThessalyTrikalaGreece
| | - Robert A. Huggins
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | | | - John F. Jardine
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - Rebecca M. Lopez
- School of Physical Therapy & Rehabilitation SciencesMorsani College of MedicineUniversity of South FloridaTampaFLUSA
| | | | - Yannis Pitisladis
- Collaborating Centre of Sports MedicineUniversity of BrightonBrightonUK
| | - Riana R. Pryor
- Department of Exercise and Nutrition SciencesCenter for Research and Education in Special EnvironmentsBuffaloNYUSA
| | - Zachary J. Schlader
- Department of KinesiologySchool of Public HealthIndiana UniversityBloomingtonIAUSA
| | - Caroline J. Smith
- Department of Health and Exercise ScienceAppalachian State UniversityBooneNCUSA
| | - Denise L. Smith
- Department of Health and Human Physiological SciencesFirst Responder Health and Safety LaboratorySkidmore CollegeSaratoga SpringsNYUSA
| | - June T. Spector
- Department of Environmental and Occupational Health SciencesSchool of Public HealthUniversity of WashingtonSeattleWAUSA
| | | | - W. Jon Williams
- Centers for Disease Control and Prevention (CDC)National Personal Protective Technology Laboratory (NPPTL)National Institute for Occupational Safety and Health (NIOSH)PittsburghPAUSA
| | - Nicole T. Vargas
- Faculty of Health SciencesUniversity of SydneySydneyNSWAustralia
| | - Susan W. Yeargin
- Department of Exercise ScienceArnold School of Public HealthUniversity of South CarolinaColumbiaSCUSA
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TURA İ, ERDEN S. Evidence-Based Recommendations For Non-Cpr First Aid Applications. KAHRAMANMARAŞ SÜTÇÜ İMAM ÜNIVERSITESI TIP FAKÜLTESI DERGISI 2021. [DOI: 10.17517/ksutfd.907345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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L'Hermette M, Castres I, Coquart J, Tabben M, Ghoul N, Andrieu B, Tourny C. Cold Water Immersion After a Handball Training Session: The Relationship Between Physical Data and Sensorial Experience. Front Sports Act Living 2020; 2:581705. [PMID: 33345150 PMCID: PMC7739586 DOI: 10.3389/fspor.2020.581705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/11/2020] [Indexed: 11/26/2022] Open
Abstract
The aim of this study was to examine the relationship between the physiological data from subjects and their reported sensory experiences during two types of recovery methods following a handball training session. Female handball players (average age: 21.4 ± 1.3 years; weight: 59.2 ± 3.3 kg; height: 158 ± 3 cm; body mass index, 23.4 ± 2.0 kg.m−2) carried out an athletic training session (rating of perceived exertion RPE: 14.70 ± 0.89) with either a passive recovery (PR) period or cold water immersion (CWI) for 14 min) (cross-over design). Physiological data were collected during the recovery period: CWI had a greater effect than PR on heart rate (HR; bpm), the higher frequencies (HF) of heart rate variability (HRV: 46.44 ± 21.50 vs. 24.12 ± 17.62), delayed onset muscle soreness (DOMS: 1.37 ± 0.51 vs. 2.12 ± 1.25), and various reported emotional sensations. Spectrum HRV analysis showed a significant increase in HF during CWI. Sensorial experiences during the recovery periods were gathered from verbatim reports 24 h later. Players' comments about CWI revealed a congruence between the physiological data and sensorial reports. They used words such as: “thermal shock,” “regeneration,” “resourcefulness,” “dynamism,” and “disappearance of pain” to describe their sensations. In conclusion, this study demonstrated the link between physiological and experiential data during CWI and we propose that action of the parasympathetic system on the autonomic nervous system can, at least in part, explain the observed correlations between the corporeal data measured and the sensorial experiences reported.
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Affiliation(s)
| | | | | | | | - Nihel Ghoul
- University of Rouen UFR STAPS, Cetaps EA, Rouen, France
| | | | - Claire Tourny
- University of Rouen UFR STAPS, Cetaps EA, Rouen, France
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Pellegrino JL, Charlton NP, Carlson JN, Flores GE, Goolsby CA, Hoover AV, Kule A, Magid DJ, Orkin AM, Singletary EM, Slater TM, Swain JM. 2020 American Heart Association and American Red Cross Focused Update for First Aid. Circulation 2020; 142:e287-e303. [PMID: 33084370 DOI: 10.1161/cir.0000000000000900] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Singletary EM, Zideman DA, Bendall JC, Berry DA, Borra V, Carlson JN, Cassan P, Chang WT, Charlton NP, Djärv T, Douma MJ, Epstein JL, Hood NA, Markenson DS, Meyran D, Orkin A, Sakamoto T, Swain JM, Woodin JA, De Buck E, De Brier N, O D, Picard C, Goolsby C, Oliver E, Klaassen B, Poole K, Aves T, Lin S, Handley AJ, Jensen J, Allan KS, Lee CC. 2020 International Consensus on First Aid Science With Treatment Recommendations. Resuscitation 2020; 156:A240-A282. [PMID: 33098920 DOI: 10.1016/j.resuscitation.2020.09.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This is the summary publication of the International Liaison Committee on Resuscitation's 2020 International Consensus on First Aid Science With Treatment Recommendations. It addresses the most recent published evidence reviewed by the First Aid Task Force science experts. This summary addresses the topics of first aid methods of glucose administration for hypoglycemia; techniques for cooling of exertional hyperthermia and heatstroke; recognition of acute stroke; the use of supplementary oxygen in acute stroke; early or first aid use of aspirin for chest pain; control of life- threatening bleeding through the use of tourniquets, haemostatic dressings, direct pressure, or pressure devices; the use of a compression wrap for closed extremity joint injuries; and temporary storage of an avulsed tooth. Additional summaries of scoping reviews are presented for the use of a recovery position, recognition of a concussion, and 6 other first aid topics. The First Aid Task Force has assessed, discussed, and debated the certainty of evidence on the basis of Grading of Recommendations, Assessment, Development, and Evaluation criteria and present their consensus treatment recommendations with evidence-to-decision highlights and identified priority knowledge gaps for future research. The 2020 International Consensus on Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care (ECC) Science With Treatment Recommendations (CoSTR) is the fourth in a series of annual summary publications from the International Liaison Committee on Resuscitation (ILCOR). This 2020 CoSTR for first aid includes new topics addressed by systematic reviews performed within the past 12 months. It also includes updates of the first aid treatment recommendations published from 2010 through 2019 that are based on additional evidence evaluations and updates. As a result, this 2020 CoSTR for first aid represents the most comprehensive update since 2010.
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12
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Singletary EM, Zideman DA, Bendall JC, Berry DC, Borra V, Carlson JN, Cassan P, Chang WT, Charlton NP, Djärv T, Douma MJ, Epstein JL, Hood NA, Markenson DS, Meyran D, Orkin AM, Sakamoto T, Swain JM, Woodin JA. 2020 International Consensus on First Aid Science With Treatment Recommendations. Circulation 2020; 142:S284-S334. [PMID: 33084394 DOI: 10.1161/cir.0000000000000897] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This is the summary publication of the International Liaison Committee on Resuscitation's 2020 International Consensus on First Aid Science With Treatment Recommendations. It addresses the most recent published evidence reviewed by the First Aid Task Force science experts. This summary addresses the topics of first aid methods of glucose administration for hypoglycemia; techniques for cooling of exertional hyperthermia and heatstroke; recognition of acute stroke; the use of supplementary oxygen in acute stroke; early or first aid use of aspirin for chest pain; control of life-threatening bleeding through the use of tourniquets, hemostatic dressings, direct pressure, or pressure devices; the use of a compression wrap for closed extremity joint injuries; and temporary storage of an avulsed tooth. Additional summaries of scoping reviews are presented for the use of a recovery position, recognition of a concussion, and 6 other first aid topics. The First Aid Task Force has assessed, discussed, and debated the certainty of evidence on the basis of Grading of Recommendations, Assessment, Development, and Evaluation criteria and present their consensus treatment recommendations with evidence-to-decision highlights and identified priority knowledge gaps for future research.
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Chemically Activated Cooling Vest's Effect on Cooling Rate Following Exercise-Induced Hyperthermia: A Randomized Counter-Balanced Crossover Study. ACTA ACUST UNITED AC 2020; 56:medicina56100539. [PMID: 33066469 PMCID: PMC7602153 DOI: 10.3390/medicina56100539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/30/2020] [Accepted: 10/09/2020] [Indexed: 11/16/2022]
Abstract
Background and objectives: Exertional heat stroke (EHS) is a potentially lethal, hyperthermic condition that warrants immediate cooling to optimize the patient outcome. The study aimed to examine if a portable cooling vest meets the established cooling criteria (0.15 °C·min−1 or greater) for EHS treatment. It was hypothesized that a cooling vest will not meet the established cooling criteria for EHS treatment. Materials and Methods: Fourteen recreationally active participants (mean ± SD; male, n = 8; age, 25 ± 4 years; body mass, 86.7 ± 10.5 kg; body fat, 16.5 ± 5.2%; body surface area, 2.06 ± 0.15 m2. female, n = 6; 22 ± 2 years; 61.3 ± 6.7 kg; 22.8 ± 4.4%; 1.66 ± 0.11 m2) exercised on a motorized treadmill in a hot climatic chamber (ambient temperature 39.8 ± 1.9 °C, relative humidity 37.4 ± 6.9%) until they reached rectal temperature (TRE) >39 °C (mean TRE, 39.59 ± 0.38 °C). Following exercise, participants were cooled using either a cooling vest (VEST) or passive rest (PASS) in the climatic chamber until TRE reached 38.25 °C. Trials were assigned using randomized, counter-balanced crossover design. Results: There was a main effect of cooling modality type on cooling rates (F[1, 24] = 10.46, p < 0.01, η2p = 0.30), with a greater cooling rate observed in VEST (0.06 ± 0.02 °C·min−1) than PASS (0.04 ± 0.01 °C·min−1) (MD = 0.02, 95% CI = [0.01, 0.03]). There were also main effects of sex (F[1, 24] = 5.97, p = 0.02, η2p = 0.20) and cooling modality type (F[1, 24] = 4.38, p = 0.047, η2p = 0.15) on cooling duration, with a faster cooling time in female (26.9 min) than male participants (42.2 min) (MD = 15.3 min, 95% CI = [2.4, 28.2]) and faster cooling duration in VEST than PASS (MD = 13.1 min, 95% CI = [0.2, 26.0]). An increased body mass was associated with a decreased cooling rate in PASS (r = −0.580, p = 0.03); however, this association was not significant in vest (r = −0.252, p = 0.39). Conclusions: Although VEST exhibited a greater cooling capacity than PASS, VEST was far below an acceptable cooling rate for EHS treatment. VEST should not replace immediate whole-body cold-water immersion when EHS is suspected.
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Golbabaei F, Heydari A, Moradi G, Dehghan H, Moradi A, Habibi P. The effect of cooling vests on physiological and perceptual responses: a systematic review. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2020; 28:223-255. [PMID: 32164499 DOI: 10.1080/10803548.2020.1741251] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Humans in hot environments are exposed to health risks and thermal discomfort which seriously affect their physical, physiological and mental workload. This study aimed to assess the effects of using cooling vests (CVs) on physiological and perceptual responses in the workplace. Three main databases were searched using subject headings and appropriate Mesh terms. The article has been written according to the preferred reporting items for systematic reviews checklist. A total of 23,837 studies were identified for screening and 63 studies were eligible for data extraction. A statistically significant difference was observed in body temperature among hybrid cooling garments (HBCGs), phase-change materials (PCMs) and air-cooled garments (ACGs) at 31.56-37 °C (60% relative humidity), evaporative cooling garments at 25.8-28.1 °C and liquid cooling garments at 35 °C (49% relative humidity) compared to without CVs (p < 0.001). HBCGs (PCMs and ACGs) are effective means in hot, moderate, humid or dry environments.
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Affiliation(s)
- Farideh Golbabaei
- Department of Occupational Health Engineering, Tehran University of Medical Sciences, Iran
| | - Ahad Heydari
- Department of Health in Disaster and Emergencies, Tehran University of Medical Sciences, Iran
| | - Gholamreza Moradi
- Department of Occupational Health Engineering, Tabriz University of Medical Sciences, Iran
| | - Habibollah Dehghan
- Department of Occupational Health Engineering, Isfahan University of Medical Sciences, Iran
| | - Amirhossein Moradi
- Faculty of Engineering and Applied Science, Memorial University of Newfoundland, Canada
| | - Peymaneh Habibi
- Department of Occupational Health Engineering, Tehran University of Medical Sciences, Iran
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Do Alternative Cooling Methods Have Effective Cooling Rates for Hyperthermia Compared With Previously Established CWI Cooling Rates? J Sport Rehabil 2020; 29:367-372. [PMID: 31628268 DOI: 10.1123/jsr.2019-0098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 06/04/2019] [Accepted: 06/19/2019] [Indexed: 11/18/2022]
Abstract
Clinical Scenario: In the last few years, there have been several studies examining alternative cooling strategies in the treatment of exertional heat stroke (EHS). Morbidity and mortality with EHS are associated with how long the patient's core body temperature remains above the critical threshold of 40.5°C. Although cold-water immersion (CWI) is the gold standard of treatment when cooling a patient with EHS, more recent alternative cooling techniques have been examined for use in settings where CWI may not be feasible (ie, remote locations). Clinical Question: Do alternative cooling methods have effective core body temperature cooling rates for hyperthermia compared with previously established CWI cooling rates? Summary of Key Findings: The authors searched for studies using alternative cooling methods to cool hyperthermic individuals. To be included, the studies needed a PEDro score ≥6 and a level of evidence ≥2. They found 9 studies related to our focused clinical question; of these, 5 studies met the inclusion criteria. The cooling rates for hand cooling, cold-water shower, and ice-sheet cooling were 0.03°C/min, 0.08°C/min, and 0.06°C/min, respectively, whereas the tarp-assisted cooling with oscillation (TACO) method was the only method that had an acceptable cooling rate (range 0.14-0.17°C/min). Clinical Bottom Line: When treating EHS, if CWI is not available, the tarp-assisted cooling method may be a reasonable alternative. Clinicians should not use cold shower, hand cooling, or ice-sheet cooling if better cooling methods are available. Clinicians should always use CWI when available. Strength of Recommendation: Five level 2 studies with PEDro scores ≥6 suggest the TACO method is the only alternative cooling method that decreases core body temperature at a similar, though slower, rate of CWI. Hand cooling, cold showering, and ice-sheet cooling do not decrease core body temperature at an appropriate rate and should not be used in EHS situations if a modality with a better cooling rate is available.
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First aid cooling techniques for heat stroke and exertional hyperthermia: A systematic review and meta-analysis. Resuscitation 2020; 148:173-190. [PMID: 31981710 DOI: 10.1016/j.resuscitation.2020.01.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 01/02/2020] [Indexed: 01/29/2023]
Abstract
BACKGROUND Heat stroke is an emergent condition characterized by hyperthermia (>40 °C/>104 °F) and nervous system dysregulation. There are two primary etiologies: exertional which occurs during physical activity and non-exertional which occurs during extreme heat events without physical exertion. Left untreated, both may lead to significant morbidity, are considered a special circumstance for cardiac arrest, and cause of mortality. METHODS We searched Medline, Embase, CINAHL and SPORTDiscus. We used Grading of Recommendations Assessment, Development and Evaluation (GRADE) methods and risk of bias assessments to determine the certainty and quality of evidence. We included randomized controlled trials, non-randomized trials, cohort studies and case series of five or more patients that evaluated adults and children with non-exertional or exertional heat stroke or exertional hyperthermia, and any cooling technique applicable to first aid and prehospital settings. Outcomes included: cooling rate, mortality, neurological dysfunction, adverse effects and hospital length of stay. RESULTS We included 63 studies, of which 37 were controlled studies, two were cohort studies and 24 were case series of heat stroke patients. Water immersion of adults with exertional hyperthermia [cold water (14-17 °C/57.2-62.6 °F), colder water (8-12 °C/48.2-53.6 °F) and ice water (1-5 °C/33.8-41 °F)] resulted in faster cooling rates when compared to passive cooling. No single water temperature range was found to be associated with a quicker core temperature reduction than another (cold, colder or ice). CONCLUSION Water immersion techniques (using 1-17 °C water) more effectively lowered core body temperatures when compared with passive cooling, in hyperthermic adults. The available evidence suggests water immersion can rapidly reduce core body temperature in settings where it is feasible.
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Abstract
Exertional heat stroke (EHS) remains one of the leading causes of sudden death in sport despite clear evidence showing 100% survivability with the proper standards of care in place and utilized. Of particular concern are student athletes competing at the secondary school level, where the extent of appropriate health care services remains suboptimal compared with organized athletics at the collegiate level and higher. While rapid recognition and rapid treatment of EHS ensures survival, the adoption and implementation of these lifesaving steps within secondary school athletics warrant further discussion within the sports medicine community. Establishing proper policies regarding the prevention and care of EHS coupled with utilizing an interdisciplinary care approach is essential for 1) minimizing risk and 2) guaranteeing optimal outcomes for the patient.
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Affiliation(s)
- William M Adams
- Department of Kinesiology, University of North Carolina at Greensboro, Greensboro, NC
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Miller KC, Di Mango TA, Katt GE. Cooling Rates of Hyperthermic Humans Wearing American Football Uniforms When Cold-Water Immersion Is Delayed. J Athl Train 2018; 53:1200-1205. [PMID: 30562055 DOI: 10.4085/1062-6050-398-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
CONTEXT Treatment delays can be contributing factors in the deaths of American football athletes from exertional heat stroke. Ideally, clinicians begin cold-water immersion (CWI) to reduce rectal temperature (Trec) to <38.9°C within 30 minutes of collapse. If delays occur, experts recommend Trec cooling rates that exceed 0.15°C/min. Whether treatment delays affect CWI cooling rates or perceptual variables when football uniforms are worn is unknown. OBJECTIVE To answer 3 questions: (1) Does wearing a football uniform and delaying CWI by 5 minutes or 30 minutes affect Trec cooling rates? (2) Do Trec cooling rates exceed 0.15°C/min when treatment delays have occurred and individuals wear football uniforms during CWI? (3) How do treatment delays affect thermal sensation and Environmental Symptoms Questionnaire responses? DESIGN Crossover study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Ten physically active men (age = 22 ± 2 y, height = 183.0 ± 6.9 cm, mass = 78.9 ± 6.0 kg). INTERVENTION(S) On 2 days, participants wore American football uniforms and exercised in the heat until Trec was 39.75°C. Then they sat in the heat, with equipment on, for either 5 or 30 minutes before undergoing CWI (10.6°C ± 0.1°C) until Trec reached 37.75°C. MAIN OUTCOME MEASURE(S) Rectal temperature and CWI duration were used to calculate cooling rates. Thermal sensation was measured pre-exercise, postexercise, postdelay, and post-CWI. Responses to the Environmental Symptoms Questionnaire were obtained pre-exercise, postdelay, and post-CWI. RESULTS The Trec cooling rates exceeded recommendations and were unaffected by treatment delays (5-minute delay = 0.20°C/min ± 0.07°C/min, 30-minute delay = 0.19°C/min ± 0.05°C/min; P = .4). Thermal sensation differed between conditions only postdelay (5-minute delay = 6.5 ± 0.6, 30-minute delay = 5.5 ± 0.7; P < .05). Environmental Symptoms Questionnaire responses differed between conditions only postdelay (5-minute delay = 27 ± 15, 30-minute delay = 16 ± 12; P < .05). CONCLUSIONS Treatment delays and football equipment did not impair CWI's effectiveness. Because participants felt cooler and better after the 30-minute delay despite still having elevated Trec, clinicians should use objective measurements (eg, Trec) to guide their decision making for patients with possible exertional heat stroke.
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Affiliation(s)
- Kevin C Miller
- School of Rehabilitation and Medical Sciences, Central Michigan University, Mount Pleasant
| | - Timothy A Di Mango
- School of Rehabilitation and Medical Sciences, Central Michigan University, Mount Pleasant
| | - Grace E Katt
- School of Rehabilitation and Medical Sciences, Central Michigan University, Mount Pleasant
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Atkins CM, Bramlett HM, Dietrich WD. Is temperature an important variable in recovery after mild traumatic brain injury? F1000Res 2017; 6:2031. [PMID: 29188026 PMCID: PMC5698917 DOI: 10.12688/f1000research.12025.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/21/2017] [Indexed: 12/03/2022] Open
Abstract
With nearly 42 million mild traumatic brain injuries (mTBIs) occurring worldwide every year, understanding the factors that may adversely influence recovery after mTBI is important for developing guidelines in mTBI management. Extensive clinical evidence exists documenting the detrimental effects of elevated temperature levels on recovery after moderate to severe TBI. However, whether elevated temperature alters recovery after mTBI or concussion is an active area of investigation. Individuals engaged in exercise and competitive sports regularly experience body and brain temperature increases to hyperthermic levels and these temperature increases are prolonged in hot and humid ambient environments. Thus, there is a strong potential for hyperthermia to alter recovery after mTBI in a subset of individuals at risk for mTBI. Preclinical mTBI studies have found that elevating brain temperature to 39°C before mTBI significantly increases neuronal death within the cortex and hippocampus and also worsens cognitive deficits. This review summarizes the pathology and behavioral problems of mTBI that are exacerbated by hyperthermia and discusses whether hyperthermia is a variable that should be considered after concussion and mTBI. Finally, underlying pathophysiological mechanisms responsible for hyperthermia-induced altered responses to mTBI and potential gender considerations are discussed.
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Affiliation(s)
- Coleen M Atkins
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Lois Pope LIFE Center, 1095 NW 14th Terrace (R-48), Miami, FL, 33136-1060, USA
| | - Helen M Bramlett
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Lois Pope LIFE Center, 1095 NW 14th Terrace (R-48), Miami, FL, 33136-1060, USA
| | - W Dalton Dietrich
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Lois Pope LIFE Center, 1095 NW 14th Terrace (R-48), Miami, FL, 33136-1060, USA
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Godek SF, Morrison KE, Scullin G. Cold-Water Immersion Cooling Rates in Football Linemen and Cross-Country Runners With Exercise-Induced Hyperthermia. J Athl Train 2017; 52:902-909. [PMID: 28937782 PMCID: PMC5687234 DOI: 10.4085/1062-6050-52.7.08] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Ideal and acceptable cooling rates in hyperthermic athletes have been established in average-sized participants. Football linemen (FBs) have a small body surface area (BSA)-to-mass ratio compared with smaller athletes, which hinders heat dissipation. OBJECTIVE To determine cooling rates using cold-water immersion in hyperthermic FBs and cross-country runners (CCs). DESIGN Cohort study. SETTING Controlled university laboratory. PATIENTS OR OTHER PARTICIPANTS Nine FBs (age = 21.7 ± 1.7 years, height = 188.7 ± 4 cm, mass = 128.1 ± 18 kg, body fat = 28.9% ± 7.1%, lean body mass [LBM] = 86.9 ± 19 kg, BSA = 2.54 ± 0.13 m2, BSA/mass = 201 ± 21.3 cm2/kg, and BSA/LBM = 276.4 ± 19.7 cm2/kg) and 7 CCs (age = 20 ± 1.8 years, height = 176 ± 4.1 cm, mass = 68.7 ± 6.5 kg, body fat = 10.2% ± 1.6%, LBM = 61.7 ± 5.3 kg, BSA = 1.84 ± 0.1 m2, BSA/mass = 268.3 ± 11.7 cm2/kg, and BSA/LBM = 298.4 ± 11.7 cm2/kg). INTERVENTION(S) Participants ingested an intestinal sensor, exercised in a climatic chamber (39°C, 40% relative humidity) until either target core temperature (Tgi) was 39.5°C or volitional exhaustion was reached, and were immediately immersed in a 10°C circulated bath until Tgi declined to 37.5°C. A general linear model repeated-measures analysis of variance and independent t tests were calculated, with P < .05. MAIN OUTCOME MEASURE(S) Physical characteristics, maximal Tgi, time to reach 37.5°C, and cooling rate. RESULTS Physical characteristics were different between groups. No differences existed in environmental measures or maximal Tgi (FBs = 39.12°C ± 0.39°C, CCs = 39.38°C ± 0.19°C; P = .12). Cooling times required to reach 37.5°C (FBs = 11.4 ± 4 minutes, CCs = 7.7 ± 0.06 minutes; P < .002) and therefore cooling rates (FBs = 0.156°C·min-1 ± 0.06°C·min-1, CCs = .255°C·min-1 ± 0.05°C·min-1; P < .002) were different. Strong correlations were found between cooling rate and body mass (r = -0.76, P < .001), total BSA (r = -0.74, P < .001), BSA/mass (r = 0.73, P < .001), LBM/mass (r = 0.72, P < .002), and LBM (r = -0.72, P < .002). CONCLUSIONS With cold-water immersion, the cooling rate in CCs (0.255°C·min-1) was greater than in FBs (0.156°C·min-1); however, both were considered ideal (≥0.155°C·min-1). Athletic trainers should realize that it likely takes considerably longer to cool large hyperthermic American-football players (>11 minutes) than smaller, leaner athletes (7.7 minutes). Cooling rates varied widely from 0.332°C·min-1 in a small runner to only 0.101°C·min-1 in a lineman, supporting the use of rectal temperature for monitoring during cooling.
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Keen ML, Miller KC, Zuhl MN. Thermoregulatory and Perceptual Effects of a Percooling Garment Worn Underneath an American Football Uniform. J Strength Cond Res 2017; 31:2983-2991. [PMID: 28858055 DOI: 10.1519/jsc.0000000000002207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Keen, ML, Miller, KC, and Zuhl, MN. Thermoregulatory and perceptual effects of a percooling garment worn underneath an American football uniform. J Strength Cond Res 31(11): 2983-2991, 2017-American football athletes are at the highest risk of developing exertional heat illness (EHI). We investigated whether percooling (i.e., cooling during exercise) garments affected perceptual or physiological variables in individuals exercising in the heat while wearing football uniforms. Twelve male participants (age = 24 ± 4 year, mass = 80.1 ± 8.5 kg, height = 182.5 ± 10.4 cm) completed this cross-over, counterbalanced study. On day 1, we measured peak oxygen consumption (V[Combining Dot Above]O2). On days 2 and 3, participants wore percooling garments with (ICE) or without (CON) ice packs over the femoral and brachial arteries. They donned a football uniform and completed 3, 20-minute bouts of treadmill exercise at ∼50% of peak V[Combining Dot Above]O2 (∼33° C, ∼42% relative humidity) followed by a 10-minute rest period. Ice packs were replaced every 20 minutes. Rating of perceived exertion (RPE), thermal sensation, and thirst sensation were measured before and after each exercise bout. Environmental symptoms questionnaire (ESQ) responses and urine specific gravity (Usg) were measured pretesting and after the last exercise bout. V[Combining Dot Above]O2, change in heart rate (ΔHR), and change in rectal temperature (ΔTrec) were measured every 5 minutes. Sweat rate, sweat volume, and percent hypohydration were calculated. No interactions (F17,187 ≤ 1.6, p ≥ 0.1) or main effect of cooling condition (F1,11 ≤ 1.4, p ≥ 0.26) occurred for ΔTrec, ΔHR, thermal sensation, thirst, RPE, ESQ, or Usg. No differences between conditions occurred for sweat volume, sweat rate, or percent hypohydration (t11 ≤ 0.7, p ≥ 0.25). V[Combining Dot Above]O2 differed between conditions over time (F15,165 = 3.3, p < 0.001); ICE was lower than CON at 30, 55, and 70 minutes (p ≤ 0.05). It is unlikely that these garments would prevent EHI or minimize dehydration in football athletes.
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Affiliation(s)
- Megan L Keen
- 1School of Rehabilitation and Medical Sciences, Central Michigan University, Mount Pleasant, Michigan; and 2School of Health Sciences, Central Michigan University, Mount Pleasant, Michigan
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Chan AP, Yang Y, Song WF, Wong DP. Hybrid cooling vest for cooling between exercise bouts in the heat: Effects and practical considerations. J Therm Biol 2017; 63:1-9. [DOI: 10.1016/j.jtherbio.2016.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 10/27/2016] [Accepted: 11/02/2016] [Indexed: 10/20/2022]
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Willmott AGB, Bliss A, Simpson WH, Tocker SM, Cottingham R, Maxwell NS. CAERvest® - a novel endothermic hypothermic device for core temperature cooling: safety and efficacy testing. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2016; 24:118-128. [PMID: 27997307 DOI: 10.1080/10803548.2016.1273640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Cooling of the body is used to treat hyperthermic individuals with heatstroke or to depress core temperature below normal for neuroprotection. A novel, chemically activated, unpowered cooling device, CAERvest®, was investigated for safety and efficacy. METHODS Eight healthy male participants (body mass 79.9 ± 1.9 kg and body fat percentage 16.1 ± 3.8%) visited the laboratory (20 °C, 40% relative humidity) on four occasions. Following 30-min rest, physiological and perceptual measures were recorded. Participants were then fitted with the CAERvest® proof of concept (PoC) or prototype 1 (P1), 2 (P2) or 3 (P3) for 60 min. Temperature, cardiovascular and perceptual measures were recorded every 5 min. After cooling, the CAERvest® was removed and the torso checked for cold-related injuries. RESULTS Temperature measures significantly (p < 0.05) reduced pre to post in all trials. Larger reductions in core and skin temperatures were observed for PoC (-0.36 ± 0.18 and -1.55 ± 0.97 °C) and P3 (-0.36 ± 0.22 and -2.47 ± 0.82 °C), compared with P1 and P2. No signs of cold-related injury were observed at any stage. CONCLUSION This study demonstrates that the CAERvest® is an effective device for reducing body temperature in healthy normothermic individuals without presence of cold injury. Further research in healthy and clinical populations is warranted.
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Affiliation(s)
- Ashley G B Willmott
- a Centre for Sport and Exercise Science and Medicine (SeSAME), Environmental Extremes Laboratory , University of Brighton , UK
| | - Alex Bliss
- a Centre for Sport and Exercise Science and Medicine (SeSAME), Environmental Extremes Laboratory , University of Brighton , UK
| | | | | | | | - Neil S Maxwell
- a Centre for Sport and Exercise Science and Medicine (SeSAME), Environmental Extremes Laboratory , University of Brighton , UK
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Luhring KE, Butts CL, Smith CR, Bonacci JA, Ylanan RC, Ganio MS, McDermott BP. Cooling Effectiveness of a Modified Cold-Water Immersion Method After Exercise-Induced Hyperthermia. J Athl Train 2016; 51:946-951. [PMID: 27874299 DOI: 10.4085/1062-6050-51.12.07] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Recommended treatment for exertional heat stroke includes whole-body cold-water immersion (CWI). However, remote locations or monetary or spatial restrictions can challenge the feasibility of CWI. Thus, the development of a modified, portable CWI method would allow for optimal treatment of exertional heat stroke in the presence of these challenges. OBJECTIVE To determine the cooling rate of modified CWI (tarp-assisted cooling with oscillation [TACO]) after exertional hyperthermia. DESIGN Randomized, crossover controlled trial. SETTING Environmental chamber (temperature = 33.4°C ± 0.8°C, relative humidity = 55.7% ± 1.9%). PATIENTS OR OTHER PARTICIPANTS Sixteen volunteers (9 men, 7 women; age = 26 ± 4.7 years, height = 1.76 ± 0.09 m, mass = 72.5 ± 9.0 kg, body fat = 20.7% ± 7.1%) with no history of compromised thermoregulation. INTERVENTION(S) Participants completed volitional exercise (cycling or treadmill) until they demonstrated a rectal temperature (Tre) ≥39.0°C. After exercise, participants transitioned to a semirecumbent position on a tarp until either Tre reached 38.1°C or 15 minutes had elapsed during the control (no immersion [CON]) or TACO (immersion in 151 L of 2.1°C ± 0.8°C water) treatment. MAIN OUTCOME MEASURE(S) The Tre, heart rate, and blood pressure (reported as mean arterial pressure) were assessed precooling and postcooling. Statistical analyses included repeated-measures analysis of variance with appropriate post hoc t tests and Bonferroni correction. RESULTS Before cooling, the Tre was not different between conditions (CON: 39.27°C ± 0.26°C, TACO: 39.30°C ± 0.39°C; P = .62; effect size = -0.09; 95% confidence interval [CI] = -0.2, 0.1). At postcooling, the Tre was decreased in the TACO (38.10°C ± 0.16°C) compared with the CON condition (38.74°C ± 0.38°C; P < .001; effect size = 2.27; 95% CI = 0.4, 0.9). The rate of cooling was greater during the TACO (0.14 ± 0.06°C/min) than the CON treatment (0.04°C/min ± 0.02°C/min; t15 = -8.84; P < .001; effect size = 2.21; 95% CI = -0.13, -0.08). These differences occurred despite an insignificant increase in fluid consumption during exercise preceding CON (0.26 ± 0.29 L) versus TACO (0.19 ± 0.26 L; t12 = 1.73; P = .11; effect size = 0.48; 95% CI = -0.02, 0.14) treatment. Decreases in heart rate did not differ between the TACO and CON conditions (t15 = -1.81; P = .09; effect size = 0.45; 95% CI = -22, 2). Mean arterial pressure was greater at postcooling with TACO (84.2 ± 6.6 mm Hg) than with CON (67.0 ± 9.0 mm Hg; P < .001; effect size = 2.25; 95% CI = 13, 21). CONCLUSIONS The TACO treatment provided faster cooling than did the CON treatment. When location, monetary, or spatial restrictions are present, TACO represents an effective alternative to traditional CWI in the emergency treatment of patients with exertional hyperthermia.
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Sefton JM, McAdam JS, Pascoe DD, Lohse KR, Banda RL, Henault CB, Cherrington AR, Adams NE. Evaluation of 2 Heat-Mitigation Methods in Army Trainees. J Athl Train 2016; 51:936-945. [PMID: 27710091 DOI: 10.4085/1062-6050-51.10.13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Heat injury is a significant threat to military trainees. Different methods of heat mitigation are in use across military units. Mist fans are 1 of several methods used in the hot and humid climate of Fort Benning, Georgia. OBJECTIVES To determine if (1) the mist fan or the cooling towel effectively lowered participant core temperature in the humid environment found at Fort Benning and (2) the mist fan or the cooling towel presented additional physiologic or safety benefits or detriments when used in this environment. DESIGN Randomized controlled clinical trial. SETTING Laboratory environmental chamber. PATIENTS OR OTHER PARTICIPANTS Thirty-five physically active men aged 19 to 35 years. INTERVENTION(S) (1) Mist fan, (2) commercial cooling towel, (3) passive-cooling (no intervention) control. All treatments lasted 20 minutes. Participants ran on a treadmill at 60% V̇o2max. MAIN OUTCOME MEASURE(S) Rectal core temperature, heart rate, thermal comfort, perceived temperature, perceived wetness, and blood pressure. RESULTS Average core temperature increased during 20 minutes of cooling (F1,28 = 64.76, P < .001, ηp2 = 0.70), regardless of group (F1,28 = 3.41, P = .08, ηp2 = 0.11) or condition (F1,28 < 1.0). Core temperature, heart rate, and blood pressure did not differ among the 3 conditions. Perceived temperature during 20 minutes of cooling decreased (F1,30 = 141.19, P < .001, ηp2 = 0.83) regardless of group or condition. Perceived temperature was lower with the mist-fan treatment than with the control treatment (F1,15 = 7.38, P = .02, ηp2 = 0.32). The mist-fan group perceived themselves to be cooler even at elevated core temperatures. CONCLUSIONS The mist fan and cooling towel were both ineffective at lowering core temperature. Core temperature continued to increase after exercise in all groups. The mist fan produced feelings of coolness while the core temperature remained elevated, possibly increasing the risk of heat illness.
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Affiliation(s)
- JoEllen M Sefton
- Warrior Research Center, School of Kinesiology, Auburn University, AL
| | - J S McAdam
- Warrior Research Center, School of Kinesiology, Auburn University, AL
| | - David D Pascoe
- Warrior Research Center, School of Kinesiology, Auburn University, AL
| | - K R Lohse
- Warrior Research Center, School of Kinesiology, Auburn University, AL
| | | | - Corbin B Henault
- Warrior Research Center, School of Kinesiology, Auburn University, AL
| | | | - N E Adams
- Warrior Research Center, School of Kinesiology, Auburn University, AL
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Comparison of different cryotherapy recovery methods in elite junior cyclists. ASIA-PACIFIC JOURNAL OF SPORT MEDICINE ARTHROSCOPY REHABILITATION AND TECHNOLOGY 2016; 5:17-23. [PMID: 29264264 PMCID: PMC5730697 DOI: 10.1016/j.asmart.2016.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Revised: 05/27/2016] [Accepted: 06/07/2016] [Indexed: 11/28/2022]
Abstract
Background/objective Cold water immersion (CWI) and active recovery treatment (ACT) are commonly used recovery treatments for athletes between exercise bouts, but they are sometimes limited by space and availability of equipment in training and competition venues. Therefore, the purpose of this study was to determine whether cold compression therapy (CCT) would provide the same effect as CWI and ACT as an alternative option in a hot environment. Methods Eight elite male junior cyclists (age, 15.5 ± 1.2 years; height, 167.7 ± 3.3 cm; body mass, 57.3 ± 3.5 kg; peak oxygen uptake, 64.7 ± 4.3 mL/kg/min) completed a maximal cycling test to determine their peak power output (PPO) and oxygen uptake. Then they completed three tests using randomised recovery protocol of CWI, CCT and ACT for 15 minutes. Each test consisted of two 35-minute exercise bouts, with 5 minutes of warm-up, 15 minutes of cycling at 75% PPO and 15 minutes maximal trial. The two exercise bouts were separated by 60 minutes (5 minutes cool-down, 10 minutes preparation for recovery treatment, 15 minutes recovery treatment, and 30 minutes passive recovery). Results There was no significant difference between average power output, blood lactate, rating of perceived exertion, and heart rate for two time-trial bouts for all recovery treatments. A significant decrease in core temperature was noted prior to the start of the second exercise bout for CWI. Conclusion CCT, CWI and ACT are all useful recovery treatments between exercise bouts.
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Zhang Y, Davis JK, Casa DJ, Bishop PA. Optimizing Cold Water Immersion for Exercise-Induced Hyperthermia: A Meta-analysis. Med Sci Sports Exerc 2016; 47:2464-72. [PMID: 25910052 DOI: 10.1249/mss.0000000000000693] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Cold water immersion (CWI) provides rapid cooling in events of exertional heat stroke. Optimal procedures for CWI in the field are not well established. This meta-analysis aimed to provide structured analysis of the effectiveness of CWI on the cooling rate in healthy adults subjected to exercise-induced hyperthermia. METHODS An electronic search (December 2014) was conducted using the PubMed and Web of Science. The mean difference of the cooling rate between CWI and passive recovery was calculated. Pooled analyses were based on a random-effects model. Sources of heterogeneity were identified through a mixed-effects model Q statistic. Inferential statistics aggregated the CWI cooling rate for extrapolation. RESULTS Nineteen studies qualified for inclusion. Results demonstrate CWI elicited a significant effect: mean difference, 0.03°C·min(-1); 95% confidence interval, 0.03-0.04°C·min(-1). A conservative, observed estimate of the CWI cooling rate was 0.08°C·min(-1) across various conditions. CWI cooled individuals twice as fast as passive recovery. Subgroup analyses revealed that cooling was more effective (Q test P < 0.10) when preimmersion core temperature ≥38.6°C, immersion water temperature ≤10°C, ambient temperature ≥20°C, immersion duration ≤10 min, and using torso plus limbs immersion. There is insufficient evidence of effect using forearms/hands CWI for rapid cooling: mean difference, 0.01°C·min(-1); 95% confidence interval, -0.01°C·min(-1) to 0.04°C·min(-1). A combined data summary, pertaining to 607 subjects from 29 relevant studies, was presented for referencing the weighted cooling rate and recovery time, aiming for practitioners to better plan emergency procedures. CONCLUSIONS An optimal procedure for yielding high cooling rates is proposed. Using prompt vigorous CWI should be encouraged for treating exercise-induced hyperthermia whenever possible, using cold water temperature (approximately 10°C) and maximizing body surface contact (whole-body immersion).
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Affiliation(s)
- Yang Zhang
- 1Chinese Badminton Association, Zhejiang Jiaxing Badminton Association, Zhejiang Province, CHINA; 2Gatorade Sports Science Institute, Barrington, IL; 3Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Storrs, CT; and 4Department of Kinesiology, University of Alabama, Tuscaloosa, AL
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Adams EL, Vandermark LW, Pryor JL, Pryor RR, VanScoy RM, Denegar CR, Huggins RA, Casa DJ. Effects of heat acclimation on hand cooling efficacy following exercise in the heat. J Sports Sci 2016; 35:828-834. [PMID: 27268072 DOI: 10.1080/02640414.2016.1192671] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This study examined the separate and combined effects of heat acclimation and hand cooling on post-exercise cooling rates following bouts of exercise in the heat. Seventeen non-heat acclimated (NHA) males (mean ± SE; age, 23 ± 1 y; mass, 75.30 ± 2.27 kg; maximal oxygen consumption [VO2 max], 54.1 ± 1.3 ml·kg-1·min-1) completed 2 heat stress tests (HST) when NHA, then 10 days of heat acclimation, then 2 HST once heat acclimated (HA) in an environmental chamber (40°C; 40%RH). HSTs were 2 60-min bouts of treadmill exercise (45% VO2 max; 2% grade) each followed by 10 min of hand cooling (C) or no cooling (NC). Heat acclimation sessions were 90-240 min of treadmill or stationary bike exercise (60-80% VO2 max). Repeated measures ANOVA with Fishers LSD post hoc (α < 0.05) identified differences. When NHA, C (0.020 ± 0.003°C·min-1) had a greater cooling rate than NC (0.013 ± 0.003°C·min-1) (mean difference [95%CI]; 0.007°C [0.001,0.013], P = 0.035). Once HA, C (0.021 ± 0.002°C·min-1) was similar to NC (0.025 ± 0.002°C·min-1) (0.004°C [-0.003,0.011], P = 0.216). Hand cooling when HA (0.021 ± 0.002°C·min-1) was similar to when NHA (0.020 ± 0.003°C·min-1) (P = 0.77). In conclusion, when NHA, C provided greater cooling rates than NC. Once HA, C and NC provided similar cooling rates.
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Affiliation(s)
- Elizabeth L Adams
- a Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology , University of Connecticut , Storrs , CT , USA.,b Department of Nutritional Sciences , The Pennsylvania State University , University Park , PA , USA
| | - Lesley W Vandermark
- a Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology , University of Connecticut , Storrs , CT , USA
| | - J Luke Pryor
- a Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology , University of Connecticut , Storrs , CT , USA.,c Department of Kinesiology , California State University , Fresno , CA , USA
| | - Riana R Pryor
- a Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology , University of Connecticut , Storrs , CT , USA.,c Department of Kinesiology , California State University , Fresno , CA , USA
| | - Rachel M VanScoy
- a Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology , University of Connecticut , Storrs , CT , USA
| | - Craig R Denegar
- a Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology , University of Connecticut , Storrs , CT , USA
| | - Robert A Huggins
- a Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology , University of Connecticut , Storrs , CT , USA
| | - Douglas J Casa
- a Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology , University of Connecticut , Storrs , CT , USA
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Butts CL, McDermott BP, Buening BJ, Bonacci JA, Ganio MS, Adams JD, Tucker MA, Kavouras SA. Physiologic and Perceptual Responses to Cold-Shower Cooling After Exercise-Induced Hyperthermia. J Athl Train 2016; 51:252-7. [PMID: 26942657 DOI: 10.4085/1062-6050-51.4.01] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Exercise conducted in hot, humid environments increases the risk for exertional heat stroke (EHS). The current recommended treatment of EHS is cold-water immersion; however, limitations may require the use of alternative resources such as a cold shower (CS) or dousing with a hose to cool EHS patients. OBJECTIVE To investigate the cooling effectiveness of a CS after exercise-induced hyperthermia. DESIGN Randomized, crossover controlled study. SETTING Environmental chamber (temperature = 33.4°C ± 2.1°C; relative humidity = 27.1% ± 1.4%). PATIENTS OR OTHER PARTICIPANTS Seventeen participants (10 male, 7 female; height = 1.75 ± 0.07 m, body mass = 70.4 ± 8.7 kg, body surface area = 1.85 ± 0.13 m(2), age range = 19-35 years) volunteered. INTERVENTION(S) On 2 occasions, participants completed matched-intensity volitional exercise on an ergometer or treadmill to elevate rectal temperature to ≥39°C or until participant fatigue prevented continuation (reaching at least 38.5°C). They were then either treated with a CS (20.8°C ± 0.80°C) or seated in the chamber (control [CON] condition) for 15 minutes. MAIN OUTCOME MEASURE(S) Rectal temperature, calculated cooling rate, heart rate, and perceptual measures (thermal sensation and perceived muscle pain). RESULTS The rectal temperature (P = .98), heart rate (P = .85), thermal sensation (P = .69), and muscle pain (P = .31) were not different during exercise for the CS and CON trials (P > .05). Overall, the cooling rate was faster during CS (0.07°C/min ± 0.03°C/min) than during CON (0.04°C/min ± 0.03°C/min; t16 = 2.77, P = .01). Heart-rate changes were greater during CS (45 ± 20 beats per minute) compared with CON (27 ± 10 beats per minute; t16 = 3.32, P = .004). Thermal sensation was reduced to a greater extent with CS than with CON (F3,45 = 41.12, P < .001). CONCLUSIONS Although the CS facilitated cooling rates faster than no treatment, clinicians should continue to advocate for accepted cooling modalities and use CS only if no other validated means of cooling are available.
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Affiliation(s)
| | | | | | | | | | - J D Adams
- University of Arkansas, Fayetteville
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Demartini JK, Casa DJ, Stearns R, Belval L, Crago A, Davis R, Jardine J. Effectiveness of cold water immersion in the treatment of exertional heat stroke at the Falmouth Road Race. Med Sci Sports Exerc 2016; 47:240-5. [PMID: 24983342 DOI: 10.1249/mss.0000000000000409] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE This study aimed to investigate the effectiveness (speed of cooling and survival rates) of cold water immersion (CWI) in the treatment of patients with exertional heat stroke (EHS). Secondly, this study aimed to compare cooling rates on the basis of gender, age, and initial rectal temperature (Tr). METHODS Eighteen years of finish line medical tent patient records were obtained from the exertional heat illness treatment area at the Falmouth Road Race. Study participants included patients with EHS who were treated with CWI in the medical tent. The number of EHS cases was recorded for each year, and incidence was established on the basis of the number of finishers. Overall cooling rate and differences between initial Tr, age, and sex were evaluated. RESULTS A total of 274 cases of EHS was observed over the 18 yr of collected data. A mean of 15.2 ± 13.0 EHS cases per year was recorded, with an overall incidence of 2.13 ± 1.62 EHS cases per 1000 finishers. The average initial Tr was 41.44°C ± 0.63°C, and the average cooling rate for patients with EHS was 0.22°C·min ± 0.11°C·min. CWI resulted in a 100% survival rate for all patients with EHS. No significant interactions between cooling rate and initial Tr (P = 0.778), sex (P = 0.89), or age (P = 0.70) were observed. CONCLUSIONS CWI was found to effectively treat all cases of EHS observed in this study. CWI provided similar treatment outcomes in all patients, with no significant differences noted on the basis of initial Tr, age, or sex. On the basis of the 100% survival rate from EHS in this large cohort, it is recommended that immediate (on site) CWI be implemented for the treatment of EHS.
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Affiliation(s)
- Julie K Demartini
- 1Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Storrs, CT; and 2Falmouth Hospital, Falmouth, MA
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Brearley M, Walker A. Water immersion for post incident cooling of firefighters; a review of practical fire ground cooling modalities. EXTREME PHYSIOLOGY & MEDICINE 2015; 4:15. [PMID: 26425341 PMCID: PMC4588265 DOI: 10.1186/s13728-015-0034-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 09/17/2015] [Indexed: 11/13/2022]
Abstract
Rapidly cooling firefighters post emergency response is likely to increase the operational effectiveness of fire services during prolonged incidents. A variety of techniques have therefore been examined to return firefighters core body temperature to safe levels prior to fire scene re-entry or redeployment. The recommendation of forearm immersion (HFI) in cold water by the National Fire and Protection Association preceded implementation of this active cooling modality by a number of fire services in North America, South East Asia and Australia. The vascularity of the hands and forearms may expedite body heat removal, however, immersion of the torso, pelvis and/or lower body, otherwise known as multi-segment immersion (MSI), exposes a greater proportion of the body surface to water than HFI, potentially increasing the rates of cooling conferred. Therefore, this review sought to establish the efficacy of HFI and MSI to rapidly reduce firefighters core body temperature to safe working levels during rest periods. A total of 38 studies with 55 treatments (43 MSI, 12 HFI) were reviewed. The core body temperature cooling rates conferred by MSI were generally classified as ideal (n = 23) with a range of ~0.01 to 0.35 °C min(-1). In contrast, all HFI treatments resulted in unacceptably slow core body temperature cooling rates (~0.01 to 0.05 °C min(-1)). Based upon the extensive field of research supporting immersion of large body surface areas and comparable logistics of establishing HFI or MSI, it is recommended that fire and rescue management reassess their approach to fireground rehabilitation of responders. Specifically, we question the use of HFI to rapidly lower firefighter core body temperature during rest periods. By utilising MSI to restore firefighter Tc to safe working levels, fire and rescue services would adopt an evidence based approach to maintaining operational capability during arduous, sustained responses. While the optimal MSI protocol will be determined by the specifics of an individual response, maximising the body surface area immersed in circulated water of up to 26 °C for 15 min is likely to return firefighter Tc to safe working levels during rest periods. Utilising cooler water temperatures will expedite Tc cooling and minimise immersion duration.
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Affiliation(s)
- Matt Brearley
- />National Critical Care and Trauma Response Centre, Level 8 Royal Darwin Hospital, Rocklands Drive, Tiwi, NT 0810 Australia
| | - Anthony Walker
- />Discipline of Sports Studies, Faculty of Health, UC Research Institute for Sport and Exercise, University of Canberra, Canberra, ACT 2601 Australia
- />Australian Capital Territory Fire and Rescue, Amberley Avenue, Fairbairn Business Park, Majura, ACT 2609 Australia
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EFFECT OF ACTIVE COOLING AND α-2 ADRENOCEPTOR ANTAGONISM ON CORE TEMPERATURE IN ANESTHETIZED BROWN BEARS (URSUS ARCTOS). J Zoo Wildl Med 2015; 46:279-85. [PMID: 26056880 DOI: 10.1638/2014-0052r.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hyperthermia is a common complication during anesthesia of bears, and it can be life threatening. The objective of this study was to evaluate the effectiveness of active cooling on core body temperature for treatment of hyperthermia in anesthetized brown bears (Ursus arctos). In addition, body temperature after reversal with atipamezole was also evaluated. Twenty-five adult and subadult brown bears were captured with a combination of zolazepam-tiletamine and xylazine or medetomidine. A core temperature capsule was inserted into the bears' stomach or 15 cm into their rectum or a combination of both. In six bears with gastric temperatures≥40.0°C, an active cooling protocol was performed, and the temperature change over 30 min was analyzed. The cooling protocol consisted of enemas with 2 L of water at approximately 5°C/100 kg of body weight every 10 min, 1 L of intravenous fluids at ambient temperature, water or snow on the paws or the inguinal area, intranasal oxygen supplementation, and removing the bear from direct sunlight or providing shade. Nine bears with body temperature>39.0°C that were not cooled served as control for the treated animals. Their body temperatures were recorded for 30 min, prior to administration of reversal. At the end of the anesthetic procedure, all bears received an intramuscular dose of atipamezole. In 10 bears, deep rectal temperature change over 30 min after administration of atipamezole was evaluated. The active cooling protocol used in hyperthermic bears significantly decreased their body temperatures within 10 min, and it produced a significantly greater decrease in their temperature than that recorded in the control group.
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Cleary MA, Toy MG, Lopez RM. Thermoregulatory, cardiovascular, and perceptual responses to intermittent cooling during exercise in a hot, humid outdoor environment. J Strength Cond Res 2014; 28:792-806. [PMID: 23897015 DOI: 10.1519/jsc.0b013e3182a20f57] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Decreasing core body temperature during exercise may improve exercise tolerance, facilitate acclimatization, and prevent heat illness during summer training. We sought to evaluate the effectiveness of intermittent superficial cooling on thermoregulatory, cardiovascular, and perceptual responses during exercise in a hot humid environment. We used a randomized, counterbalanced, repeated measures investigation with 2 conditions (control and cooling) during exercise and recovery outdoors on artificial turf in a hot, humid tropical climate in the sun (wet bulb globe temperature outdoors [WBGTo], 27.0 ± 0.8° C; range, 25.8-28.1° C) and in the shade (WBGTo, 25.4 ± 0.9° C; range, 24.3-26.8° C). Participants were 10 healthy males (age, 22.6 ± 1.6 years; height, 176.0 ± 6.9 cm; mass, 76.5 ± 7.8 kg; body fat, 15.6 ± 5.4%) who wore shorts and T-shirt (control) or "phase change cooling" vest (cooling) during 5-minute rest breaks during 60 minutes of intense American football training and conditioning exercises in the heat and 30 minutes of recovery in the shade. Throughout, we measured core (Tgi) and skin (Tchest) temperature, heart rate (HR), thermal and thirst sensations, and rating of perceived exertion. We found significant (p ≤ 0.001) hypohydration (-2.1%); for Tgi, we found no significant differences between conditions (p = 0.674) during exercise and progressive decreases during recovery (p < 0.001). For [INCREMENT]Tg,i we found no significant (p = 0.090) differences. For Tchest, we found significantly (p < 0.001) decreased skin temperature in the cooling condition (Tchest, 31.85 ± 0.43° C) compared with the control condition (Tchest, 34.38 ± 0.43° C) during exercise and significantly (p < 0.001) lower skin temperature in the cooling condition (Tchest, 31.24 ± 0.47° C) compared with the control condition (Tchest, 33.48 ± 0.47° C) during recovery. For HR, we found no significant difference (p = 0.586) between the conditions during exercise; however, we did find significantly (p < 0.001) lower HR during recovery. Thermal sensations were significantly (p = 0.026) decreased in the cooling (4.4 ± 0.2 points) compared with the control (5.0 ± 0.2 points) condition but not for other perceptual responses. The cooling effects of "phase change cooling" material were effective in reducing skin temperature but did not sufficiently reduce core body temperature or cardiovascular strain.
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Affiliation(s)
- Michelle A Cleary
- 1Athletic Training Education Program, College of Educational Studies, Chapman University, Orange, California; 2Dellarmine College Preparatory, San Jose, California; and 3Department of Orthopedics and Sports Medicine, University of South Florida, Tampa, Florida
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Glasgow PD, Ferris R, Bleakley CM. Cold water immersion in the management of delayed-onset muscle soreness: Is dose important? A randomised controlled trial. Phys Ther Sport 2014; 15:228-33. [DOI: 10.1016/j.ptsp.2014.01.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 10/23/2013] [Accepted: 01/16/2014] [Indexed: 11/16/2022]
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Titus DJ, Furones C, Atkins CM, Dietrich WD. Emergence of cognitive deficits after mild traumatic brain injury due to hyperthermia. Exp Neurol 2014; 263:254-62. [PMID: 25447938 DOI: 10.1016/j.expneurol.2014.10.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 10/16/2014] [Accepted: 10/22/2014] [Indexed: 02/04/2023]
Abstract
Mild elevations in core temperature can occur in individuals involved in strenuous activities that are risky for potentially sustaining a mild traumatic brain injury (mTBI) or concussion. Recently, we have discovered that mild elevations in brain temperature can significantly aggravate the histopathological consequences of mTBI. However, whether this exacerbation of brain pathology translates into behavioral deficits is unknown. Therefore, we investigated the behavioral consequences of elevating brain temperature to mildly hyperthermic levels prior to mTBI. Adult male Sprague Dawley rats underwent mild fluid-percussion brain injury or sham surgery while normothermic (37 °C) or hyperthermic (39 °C) and were allowed to recover for 7 days. Animals were then assessed for cognition using the water maze and cue and contextual fear conditioning. We found that mTBI alone at normothermia had no effect on long-term cognitive measures whereas mTBI animals that were hyperthermic for 15 min prior to and for 4h after brain injury were significantly impaired on long-term retention for both the water maze and fear conditioning. In contrast, hyperthermic mTBI animals cooled within 15 min to normothermia demonstrated no significant long-term cognitive deficits. Mild TBI irrespective of temperature manipulations resulted in significant short-term working memory deficits. Cortical atrophy and contusions were detected in all mTBI treatment groups and contusion volume was significantly less in hyperthermic mTBI animals that were cooled as compared to hyperthermic mTBI animals that remained hyperthermic. These results indicate that brain temperature is an important variable for mTBI outcome and that mildly elevated temperatures at the time of injury result in persistent cognitive deficits. Importantly, cooling to normothermia after mTBI prevents the development of long-term cognitive deficits caused by hyperthermia. Reducing temperature to normothermic levels soon after mTBI represents a rational approach to potentially mitigate the long-term consequences of mTBI.
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Affiliation(s)
- David J Titus
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Concepcion Furones
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Coleen M Atkins
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - W Dalton Dietrich
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA.
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Cryotherapy with dynamic intermittent compression for analgesia after anterior cruciate ligament reconstruction. Preliminary study. Orthop Traumatol Surg Res 2014; 100:309-12. [PMID: 24679367 DOI: 10.1016/j.otsr.2013.12.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 12/07/2013] [Accepted: 12/16/2013] [Indexed: 02/02/2023]
Abstract
BACKGROUND Cryotherapy is a useful adjunctive analgesic measure in patients with postoperative pain following anterior cruciate ligament (ACL) surgery. Either static permanent compression or dynamic intermittent compression can be added to increase the analgesic effect of cryotherapy. Our objective was to compare the efficacy of these two compression modalities combined with cryotherapy in relieving postoperative pain and restoring range of knee motion after ligament reconstruction surgery. HYPOTHESIS When combined with cryotherapy, a dynamic and intermittent compression is associated with decreased analgesic drug requirements, less postoperative pain, and better range of knee motion compared to static compression. MATERIALS AND METHODS We conducted a case-control study of consecutive patients who underwent anterior cruciate ligament reconstruction at a single institution over a 3-month period. Both groups received the same analgesic drug protocol. One group was managed with cryotherapy and dynamic intermittent compression (Game Ready(®)) and the other with cryotherapy and static compression (IceBand(®)). RESULTS Of 39 patients, 20 received dynamic and 19 static compression. In the post-anaesthesia recovery unit, the mean visual analogue scale (VAS) pain score was 2.4 (range, 0-6) with dynamic compression and 2.7 (0-7) with static compression (P=0.3); corresponding values were 1.85 (0-9) vs. 3 (0-8) (P=0.16) after 6 hours and 0.6 (0-3) vs. 1.14 (0-3) (P=0.12) at discharge. The cumulative mean tramadol dose per patient was 57.5mg (0-200mg) with dynamic compression and 128.6 mg (0-250 mg) with static compression (P=0.023); corresponding values for morphine were 0mg vs. 1.14 mg (0-8 mg) (P<0.05). Mean range of knee flexion at discharge was 90.5° (80°-100°) with dynamic compression and 84.5° (75°-90°) with static compression (P=0.0015). CONCLUSION Dynamic intermittent compression combined with cryotherapy decreases analgesic drug requirements after ACL reconstruction and improves the postoperative recovery of range of knee motion. LEVEL OF EVIDENCE Level III, case-control study.
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Pryor RR, Casa DJ, Adams WM, Belval LN, DeMartini JK, Huggins RA, Stearns RL, Vandermark LW. Maximizing Athletic Performance in the Heat. Strength Cond J 2013. [DOI: 10.1519/ssc.0000000000000016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Lopez RM, Eberman LE, Cleary MA. Superficial cooling does not decrease core body temperature before, during, or after exercise in an American football uniform. J Strength Cond Res 2013; 26:3432-40. [PMID: 23007493 DOI: 10.1519/jsc.0b013e3182736e5b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of this study was to identify the effects of superficial cooling on thermoregulatory responses while exercising in a hot humid environment while wearing an American football uniform. Nine male and female subjects wore a superficial cooling garment while in a cooling (CS) experimental condition or a no cooling (NCS) control condition during an exercise task consisting of warm-up (WU), exercise (EX), and recovery (R). The exercise task simulated an American football conditioning session with subjects wearing a full American football uniform and performing anaerobic and aerobic exercises in a hot humid environment. Subjects were allowed to drink water ad libitum during rest breaks. During the WU, EX, and R periods, core body temperature (T(c)) was measured to assess the effect of the cooling garment. Neither baseline resting before warm-up T(c) nor after warm-up T(c) was significantly different between trials. No significant differences in exercise T(c) between conditions were found. Time to return to baseline T(c) revealed no significant differences between the experimental and control conditions. The authors found that the volume of fluid consumed was 34% less in the experimental condition (711.1 ± 188.0 ml) compared with the control condition (1,077.8 ± 204.8 ml). The findings indicate that the cooling garment was not effective in blunting the rise in T(c) during warm-up, attenuating a rise in T(c) during intermittent exercise, or in increasing a return to baseline T(c) during a resting recovery period in a hot humid environment while wearing an American football uniform.
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Affiliation(s)
- Rebecca M Lopez
- Department of Orthopedics & Sports Medicine, University of South Florida, Tampa, Florida, USA.
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Prado FP, Paludetto DRB, Bachur CAK, Freitas RALD, Zaia JE, Barros Neto TL, Garcia SB, Alves ACA, Carvalho PTCD, Bachur JA. Estresse oxidativo no plasma sanguíneo de indivíduos submetidos ao esforço físico agudo seguido de crioimersão corporal. FISIOTERAPIA E PESQUISA 2012. [DOI: 10.1590/s1809-29502012000300005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
O objetivo deste estudo foi analisar a influência da crioimersão corporal (CIC) imediata ao esforço físico agudo no estresse oxidativo (EOx) no plasma sanguíneo. Participaram do presente estudo 12 homens, com idade média de 22±1 anos, submetidos ao teste de esforço físico intenso em esteira, seguido de CIC em um tanque com água a 10ºC durante 10 minutos contínuos. Do repouso ao final da CIC, os indivíduos foram monitorados através de alguns parâmetros como: o índice de percepção subjetiva do esforço (IPE) expresso conforme escala de Borg, frequência cardíaca (FC), pressão arterial (PA) e temperatura corporal (TC) através da temperatura timpânica. A análise morfológica do EOx plasmático foi realizada de acordo com o método denominado Morfologia Óptica do Estresse Oxidativo no Plasma (MEOP), utilizando-se gotas de sangue capilar. Observou-se uma significativa elevação (p<0,01) no grau do estresse oxidativo plasmático após a realização do esforço físico, em relação ao respectivo grau em repouso. Porém, esta elevação no grau do EOx foi significativamente reduzida (p<0,001) em função da CIC. Embora sejam necessários mais estudos científicos com o MEOP, concluiu-se que, para o presente estudo, este teste mostrou-se viável. Os dados encontrados no presente estudo sugerem que a CIC em água a 10ºC por 10 minutos imediatos ao esforço físico agudo com intensidade alta, apresenta-se como uma importante conduta fisioterapêutica para a normalização do EOx pós-esforço.
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