Should Cooling Vests Be Used to Treat Exertional Heatstroke? A Critically Appraised Topic

2017 ◽  
Vol 26 (3) ◽  
pp. 286-289
Author(s):  
Megan L. Keen ◽  
Kevin C. Miller
Keyword(s):  
Cold Water ◽  
Core Body Temperature ◽  
Water Immersion ◽  
Heat Stroke ◽  
Cold Water Immersion ◽  
Clinical Scenario ◽  
Clinical Question ◽  
Bottom Line ◽  
Cooling Rates ◽  
Central Nervous System Dysfunction

Clinical Scenario:Exercise performed in hot and humid environments increases core body temperature (TC). If TC exceeds 40.5°C for prolonged periods of time, exertional heat stroke (EHS) may occur. EHS is a leading cause of sudden death in athletes. Mortality and morbidity increase the longer the patient’s TC remains above 40.5°C; thus, it is imperative to initiate cooling as quickly as possible. Acceptable cooling rates in EHS situations are 0.08–0.15°C/min, while ideal cooling rates are above 0.16°C/min. Cooling vests are popular alternatives for cooling hyperthermic adults. Most vests cover the anterior and posterior torso and have varying numbers of pouches for phase-change materials (eg, gel packs); some vests only use circulating water to cool. While cooling vests offer several advantages (eg, portability), studies demonstrating their effectiveness at rapidly reducing TC in EHS scenarios are limited.Clinical Question:Are TC cooling rates acceptable (ie, >0.08°C/min) when hyperthermic humans are treated with cooling vests postexercise?Summary of Findings:No significant differences in TC cooling rates occurred between cooling vests and no cooling vests. Cooling rates across all studies were ≤0.053°C/min.Clinical Bottom Line:Cooling vests do not provide acceptable cooling rates of hyperthermic humans postexercise and should not be used to treat EHS. Instead, EHS patients should be treated with cold-water immersion within 30 min of collapse to avoid central nervous system dysfunction and organ failure.Strength of Recommendation:Strong evidence (eg, level 2 studies with PEDro scores ≥5) suggests that cooling vests do not reduce TC quickly and thus should not be used in EHS scenarios.

Can Temperate-Water Immersion Effectively Reduce Rectal Temperature in Exertional Heat Stroke? A Critically Appraised Topic

2017 ◽  
Vol 26 (5) ◽  
pp. 447-451 ◽  
Author(s):  
Tyler T. Truxton ◽  
Kevin C. Miller
Keyword(s):  
Rectal Temperature ◽  
Water Immersion ◽  
Heat Stroke ◽  
Medical Emergency ◽  
Clinical Scenario ◽  
Clinical Question ◽  
Temperate Water ◽  
Bottom Line ◽  
Exertional Heat Stroke ◽  
Cooling Rates

Clinical Scenario:Exertional heat stroke (EHS) is a medical emergency which, if left untreated, can result in death. The standard of care for EHS patients includes confirmation of hyperthermia via rectal temperature (Trec) and then immediate cold-water immersion (CWI). While CWI is the fastest way to reduce Trec, it may be difficult to lower and maintain water bath temperature in the recommended ranges (1.7°C–15°C [35°F–59°F]) because of limited access to ice and/or the bath being exposed to high ambient temperatures for long periods of time. Determining if Trec cooling rates are acceptable (ie, >0.08°C/min) when significantly hyperthermic humans are immersed in temperate water (ie, ≥20°C [68°F]) has applications for how EHS patients are treated in the field.Clinical Question:Are Trec cooling rates acceptable (≥0.08°C/min) when significantly hyperthermic humans are immersed in temperate water?Summary of Findings:Trec cooling rates of hyperthermic humans immersed in temperate water (≥20°C [68°F]) ranged from 0.06°C/min to 0.19°C/min. The average Trec cooling rate for all examined studies was 0.11±0.06°C/min.Clinical Bottom Line:Temperature water immersion (TWI) provides acceptable (ie, >0.08°C/min) Trec cooling rates for hyperthermic humans post-exercise. However, CWI cooling rates are higher and should be used if feasible (eg, access to ice, shaded treatment areas).Strength of Recommendation:The majority of evidence (eg, Level 2 studies with PEDro scores ≥5) suggests TWI provides acceptable, though not ideal, Trec cooling. If possible, CWI should be used instead of TWI in EHS scenarios.

Athletic Trainers' Attitudes and Perceptions Regarding Exertional Heat Stroke Before and After an Educational Intervention

2017 ◽  
Vol 12 (3) ◽  
pp. 179-187 ◽  
Author(s):  
Kristen Couper Schellhase ◽  
Jennifer Plant ◽  
Stephanie M. Mazerolle
Keyword(s):  
Educational Intervention ◽  
Cold Water ◽  
Core Body Temperature ◽  
Athletic Trainers ◽  
Water Immersion ◽  
Heat Stroke ◽  
Cold Water Immersion ◽  
Attitudes And Perceptions ◽  
Before And After ◽  
Core Body

Context: Death from exertional heat stroke (EHS) is preventable when evidence-based guidelines are followed. The assessment of core body temperature using rectal thermometry and the treatment of cold-water immersion for EHS has been established as the standard of care; however, rectal thermometry is still controversial. Athletic trainers (ATs) may lack knowledge and comfort with this skill, which could impact implementation. Objective: Examine ATs' current practices, attitudes, and perceptions regarding EHS before and after an educational intervention. Design: Prequantitative/postquantitative experimental. Setting: Classroom. Patients or Other Participants: Twenty-five ATs in various athletic training settings. Intervention(s): Educational intervention designed to increase knowledge and address negative attitudes and perceptions regarding EHS evaluation and treatment. Main Outcome Measure(s): Attitude and perception scores. Results: Prior to the educational intervention, most ATs (86.9%, 20/23) reported that they use methods other than rectal thermometry to evaluate EHS. Of those who did not use rectal thermometry, their reasons included: lack of equipment/budget, concerns about liability/lack of consent (especially when dealing with minors), lack of training, and/or concerns about the privacy, embarrassment, compliance of the athlete. Cold-water immersion was chosen as the definitive method of cooling an athlete by only 41.7% (n = 10) of participants. Following the educational intervention, attitudes toward the use of rectal temperature to assess core body temperature (t[24] = 8.663, P < .001) and cold-water immersion treatment for EHS (t[24] = 4.187, P < .001) were significantly improved. However, while attitudes toward the use of other “cold” methods to treat EHS were not significantly changed (t[24] = 1.684, P = .105), perceptions regarding nonexertional influences on EHS were significantly improved (t[24] = 1.684, P = .105). Conclusions: This study demonstrated that a 3-hour educational intervention can improve attitudes and perceptions regarding the assessment and treatment of EHS in the short term. It is important that educational interventions use best-practice continuing education methods and include special attention to the barriers to evidence-based practice.

scholarly journals Necessity of Removing American Football Uniforms From Humans With Hyperthermia Before Cold-Water Immersion

2015 ◽  
Vol 50 (12) ◽  
pp. 1240-1246 ◽  
Author(s):  
Kevin C. Miller ◽  
Blaine C. Long ◽  
Jeffrey Edwards
Keyword(s):  
Sports Medicine ◽  
Cold Water ◽  
Thermal Sensation ◽  
Water Immersion ◽  
Heat Stroke ◽  
Cold Water Immersion ◽  
American Football ◽  
Body Core Temperature ◽  
Cooling Rates ◽  
National Athletic Trainers Association

Context  The National Athletic Trainers' Association and the American College of Sports Medicine have recommended removing American football uniforms from athletes with exertional heat stroke before cold-water immersion (CWI) based on the assumption that the uniform impedes rectal temperature (Trec) cooling. Few experimental data exist to verify or disprove this assumption and the recommendations. Objectives  To compare CWI durations, Trec cooling rates, thermal sensation, intensity of environmental symptoms, and onset of shivering when hyperthermic participants wore football uniforms during CWI or removed the uniforms immediately before CWI. Design  Crossover study. Setting  Laboratory. Patients or Other Participants  Eighteen hydrated, physically active men (age = 22 ± 2 years, height = 182.5 ± 6.1 cm, mass = 85.4 ± 13.4 kg, body fat = 11% ± 5%, body surface area = 2.1 ± 0.2 m2) volunteered. Intervention(s)  On 2 days, participants exercised in the heat (approximately 40°C, approximately 40% relative humidity) while wearing a full American football uniform (shoes; crew socks; undergarments; shorts; game pants; undershirt; shoulder pads; jersey; helmet; and padding over the thighs, knees, hips, and tailbone [PADS]) until Trec reached 39.5°C. Next, participants immersed themselves in water that was approximately 10°C while wearing either undergarments, shorts, and crew socks (NOpads) or PADS without shoes until Trec reached 38°C. Main Outcome Measure(s)  The CWI duration (minutes) and Trec cooling rates (°C/min). Results  Participants had similar exercise times (NOpads = 40.8 ± 4.9 minutes, PADS = 43.2 ± 4.1 minutes; t17 = 2.0, P = .10), hypohydration levels (NOpads = 1.5% ± 0.3%, PADS = 1.6% ± 0.4%; t17 = 1.3, P = .22), and thermal-sensation ratings (NOpads = 7.2 ± 0.3, PADS = 7.1 ± 0.5; P > .05) before CWI. The CWI duration (median [interquartile range]; NOpads = 6.0 [5.4] minutes, PADS = 7.3 [9.8] minutes; z = 2.3, P = .01) and Trec cooling rates (NOpads = 0.28°C/min ± 0.14°C/min, PADS = 0.21°C/min ± 0.11°C/min; t17 = 2.2, P = .02) differed between uniform conditions. Conclusions  Whereas participants cooled faster in NOpads, we still considered the PADS cooling rate to be acceptable (ie, >0.16°C/min). Therefore, if clinicians experience difficulty removing PADS or CWI treatment is delayed, they may immerse fully equipped hyperthermic football players in CWI and maintain acceptable Trec cooling rates. Otherwise, PADS should be removed preimmersion to ensure faster body core temperature cooling.

scholarly journals Cooling Capacity of Transpulmonary Cooling and Cold-Water Immersion After Exercise-Induced Hyperthermia

2021 ◽  
Vol 56 (4) ◽  
pp. 383-388
Author(s):  
William M. Adams ◽  
Erin E. Butke ◽  
Junyong Lee ◽  
Mitchell E. Zaplatosch
Keyword(s):  
Cold Water ◽  
Water Immersion ◽  
Heat Stroke ◽  
Cooling Capacity ◽  
Cold Water Immersion ◽  
Peak Oxygen Uptake ◽  
Treatment Modalities ◽  
Controlled Clinical Trial ◽  
Cooling Rates ◽  
Adjunct Treatment

Context Cold-water immersion (CWI) may not be feasible in some remote settings, prompting the identification of alternative cooling methods as adjunct treatment modalities for exertional heat stroke (EHS). Objective To determine the differences in cooling capacities between CWI and the inhalation of cooled air. Design Randomized controlled clinical trial. Setting Laboratory. Patients or Other Participants A total of 12 recreationally active participants (7 men, 5 women; age = 26 ± 4 years, height = 170.6 ± 10.1 cm, mass = 76.0 ± 18.0 kg, body fat = 18.5% ± 9.7%, peak oxygen uptake = 42.7 ± 8.9 mL·kg−1·min−1). Intervention(s) After exercise in a hot environment (40°C and 40% relative humidity), participants were randomized to 3 cooling conditions: cooling during passive rest (PASS; control), CWI, and the Polar Breeze thermal rehabilitation machine (PB) with which participants inspired cooled air (22.2°C ± 1.0°C). Main Outcome Measure(s) Rectal temperature (TREC) and heart rate were continuously measured throughout cooling until TREC reached 38.25°C. Results Cooling rates during CWI (0.18°C·min−1 ± 0.06°C·min−1) were greater than those during PASS (mean difference [95% CI] of 0.16°C·min−1 [0.13°C·min−1, 0.19°C·min−1]; P < .001) and PB (0.15°C·min−1 [0.12°C·min−1, 0.16°C·min−1]; P < .001). Elapsed time to reach a TREC of 38.25°C was also faster with CWI (9.71 ± 3.30 minutes) than PASS (−58.1 minutes [−77.1, −39.9 minutes]; P < .001) and PB (−46.8 minutes [−65.5, −28.2 minutes]; P < .001). Differences in cooling rates and time to reach a TREC of 38.25°C between PASS and PB were not different (P > .05). Conclusions Transpulmonary cooling via cooled-air inhalation did not promote an optimal cooling rate (>0.15°C·min−1) for the successful treatment of EHS. In remote settings where EHS is a risk, access and use of treatment methods via CWI or cold-water dousing are imperative to ensuring survival. Trial Registry ClinicalTrials.gov (NCT0419026).

scholarly journals Cooling Rates of Hyperthermic Humans Wearing American Football Uniforms When Cold-Water Immersion Is Delayed

2018 ◽  
Vol 53 (12) ◽  
pp. 1200-1205 ◽  
Author(s):  
Kevin C. Miller ◽  
Timothy A. Di Mango ◽  
Grace E. Katt
Keyword(s):  
Rectal Temperature ◽  
Cold Water ◽  
Thermal Sensation ◽  
Water Immersion ◽  
Heat Stroke ◽  
Cold Water Immersion ◽  
American Football ◽  
Exertional Heat Stroke ◽  
Cooling Rates ◽  
Treatment Delays

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.

The Effects of Cold Water Immersion on Postexercise Muscle Soreness and Fatigue

2016 ◽  
Vol 21 (2) ◽  
pp. 4-11
Author(s):  
Christina J. Lorete ◽  
Riley N. Fontaine ◽  
Lauren A. Welsch ◽  
Johanna M. Hoch
Keyword(s):  
Muscle Fatigue ◽  
Cold Water ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Clinical Question ◽  
Bottom Line ◽  
Physically Active ◽  
Postexercise Recovery ◽  
Active Adults ◽  
Quality Evidence

Clinical Question:Is there evidence to suggest continuous cold water immersion (CWI) as a postexercise recovery intervention is more effective at reducing perceived muscle fatigue or soreness as measured using a Visual Analog Scale (VAS) when compared with passive rest in physically active adults?Summary of Key Findings:A systematic search of the literature produced 124 studies, with two randomized controlled trials and two cross-over studies meeting the inclusion criteria.Clinical Bottom Line:There is inconsistent, limited-quality evidence to support that the use of CWI postexercise is more effective at reducing perceived muscle fatigue or soreness in physically active adults when compared with passive rest. The results of the included studies were inconsistent regarding the application of continuous CWI for 10–14 min to reduce perceived muscle fatigue and soreness when compared with passive rest. The good-quality evidence found no difference between conditions and the three limited-quality studies identified differences between the conditions.

scholarly journals Safety and efficacy of cold‐water immersion in the treatment of older patients with heat stroke: a case series

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Chikao Ito ◽  
Isao Takahashi ◽  
Miyuki Kasuya ◽  
Kyoji Oe ◽  
Masahito Uchino ◽  
...  
Keyword(s):  
Older Patients ◽  
Cold Water ◽  
Water Immersion ◽  
Heat Stroke ◽  
Case Series ◽  
Cold Water Immersion ◽  
Safety And Efficacy

Effectiveness of Cold Water Immersion in the Treatment of Exertional Heat Stroke at the Falmouth Road Race

2015 ◽  
Vol 47 (2) ◽  
pp. 240-245 ◽  
Author(s):  
JULIE K. DEMARTINI ◽  
DOUGLAS J. CASA ◽  
REBECCA STEARNS ◽  
LUKE BELVAL ◽  
ARTHUR CRAGO ◽  
...  
Keyword(s):  
Cold Water ◽  
Water Immersion ◽  
Heat Stroke ◽  
Cold Water Immersion ◽  
Exertional Heat Stroke ◽  
Road Race

scholarly journals Physiologic and Perceptual Responses to Cold-Shower Cooling After Exercise-Induced Hyperthermia

2016 ◽  
Vol 51 (3) ◽  
pp. 252-257 ◽  
Author(s):  
Cory L. Butts ◽  
Brendon P. McDermott ◽  
Brian J. Buening ◽  
Jeffrey A. Bonacci ◽  
Matthew S. Ganio ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cooling Rate ◽  
Rectal Temperature ◽  
Muscle Pain ◽  
Cold Water ◽  
Thermal Sensation ◽  
Water Immersion ◽  
Heat Stroke ◽  
Cold Water Immersion ◽  
Exercise Induced

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.Context: To investigate the cooling effectiveness of a CS after exercise-induced hyperthermia.Objective: Randomized, crossover controlled study.Design: Environmental chamber (temperature = 33.4°C ± 2.1°C; relative humidity = 27.1% ± 1.4%).Setting: 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 m2, age range = 19–35 years) volunteered.Patients or Other Participants: 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.Intervention(s): Rectal temperature, calculated cooling rate, heart rate, and perceptual measures (thermal sensation and perceived muscle pain).Main Outcome Measure(s): 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).Results: 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.Conclusions:

scholarly journals Loss of α-actinin-3 during human evolution provides superior cold resilience and muscle heat generation

2020 ◽  
Author(s):  
VL Wyckelsma ◽  
T Venckunas ◽  
PJ Houweling ◽  
M Schlittler ◽  
VM Lauschke ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cold Tolerance ◽  
Muscle Activation ◽  
Cold Water ◽  
Muscle Protein ◽  
Core Body Temperature ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Skeletal Muscle Protein ◽  
Brown Adipose

ABSTRACTThe fast skeletal muscle protein α-actinin-3 is absent in 1.5 billion people worldwide due to homozygosity for a nonsense polymorphism in the ACTN3 gene (R577X) 1. The prevalence of the 577X allele increased as modern humans moved to colder climates, suggesting a link between α-actinin-3 deficiency and improved cold tolerance 1,2. Here, we show that humans lacking α-actinin-3 (XX) are superior in maintaining core body temperature during cold-water immersion due to changes in skeletal muscle thermogenesis. Muscles of XX individuals displayed a shift towards more slow-twitch isoforms of myosin heavy chain (MyHC) and sarcoplasmic reticulum (SR) proteins, accompanied by altered neuronal muscle activation resulting in increased tone rather than overt shivering 3,4. Experiments on Actn3 knockout mice showed no alterations in brown adipose tissue (BAT) properties that could explain the improved cold tolerance in XX individuals. Thus, this study provides a clear mechanism for the positive selection of the ACTN3 X-allele in cold climates and supports a key thermogenic role of skeletal muscle during cold exposure in humans.

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