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Flouris AD, Notley SR, Stearns RL, Casa DJ, Kenny GP. Recommended water immersion duration for the field treatment of exertional heat stroke when rectal temperature is unavailable. Eur J Appl Physiol 2024; 124:479-490. [PMID: 37552243 DOI: 10.1007/s00421-023-05290-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/14/2023] [Indexed: 08/09/2023]
Abstract
INTRODUCTION The recommended treatment for exertional heat stroke is immediate, whole-body immersion in < 10 °C water until rectal temperature (Tre) reaches ≤ 38.6 °C. However, real-time Tre assessment is not always feasible or available in field settings or emergency situations. We defined and validated immersion durations for water temperatures of 2-26 °C for treating exertional heat stroke. METHODS We compiled data for 54 men and 18 women from 7 previous laboratory studies and derived immersion durations for reaching 38.6 °C Tre. The resulting immersion durations were validated against the durations of cold-water immersion used to treat 162 (98 men; 64 women) exertional heat stroke cases at the Falmouth Road Race between 1984 and 2011. RESULTS Age, height, weight, body surface area, body fat, fat mass, lean body mass, and peak oxygen uptake were weakly associated with the cooling time to a safe Tre of 38.6 °C during immersions to 2-26 °C water (R2 range: 0.00-0.16). Using a specificity criterion of 0.9, receiver operating characteristics curve analysis showed that exertional heat stroke patients must be immersed for 11-12 min when water temperature is ≤ 9 °C, and for 18-19 min when water temperature is 10-26 °C (Cohen's Kappa: 0.32-0.75, p < 0.001; diagnostic odds ratio: 8.63-103.27). CONCLUSION The reported immersion durations are effective for > 90% of exertional heat stroke patients with pre-immersion Tre of 39.5-42.8 °C. When available, real-time Tre monitoring is the standard of care to accurately diagnose and treat exertional heat stroke, avoiding adverse health outcomes associated with under- or over-cooling, and for implementing cool-first transport second exertional heat stroke policies.
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Affiliation(s)
- Andreas D Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Sean R Notley
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
- Defence Science and Technology Group, Melbourne, VIC, Australia
| | - Rebecca L Stearns
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT, USA
| | - Douglas J Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT, USA
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada.
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.
- Montpetit Hall, 125 University Private, Room 367, Ottawa, ON, K1N 6N5, Canada.
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Hutchins KP, Minett GM, Stewart IB. Treating exertional heat stroke: Limited understanding of the female response to cold water immersion. Front Physiol 2022; 13:1055810. [PMID: 36505067 PMCID: PMC9732943 DOI: 10.3389/fphys.2022.1055810] [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: 09/28/2022] [Accepted: 11/02/2022] [Indexed: 11/26/2022] Open
Abstract
According to an expansive body of research and best practice statements, whole-body cold water immersion is the gold standard treatment for exertional heat stroke. However, as this founding evidence was predominantly drawn from males, the current guidelines for treatment are being applied to women without validation. Given the recognised differences in thermal responses experienced by men and women, all-encompassing exertional heat stroke treatment advice may not effectively protect both sexes. In fact, recent evidence suggests that hyperthermic women cool faster than hyperthermic men during cold water immersion. This raises the question of whether overcooling is risked if the present guidelines are followed. The current mini-review examined the literature on women's response to cold water immersion as a treatment for exertional heat stroke and aimed to clarify whether the current guidelines have appropriately considered research investigating women. The potential implications of applying these guidelines to women were also discussed.
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Koenig FS, Miller KC, O'Connor P, Amaria N. Body Anthropometrics and Rectal Temperature Cooling Rates in Women With Hyperthermia. J Athl Train 2022; 57:464-469. [PMID: 35230443 PMCID: PMC9205556 DOI: 10.4085/1062-6050-225-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Cold-water immersion (CWI) is the best treatment for exertional heat stroke (EHS), and rectal temperature (Trec) cooling rates may differ between sexes. Previous authors have suggested body surface area (BSA) to lean body mass (LBM) ratio is the largest factor affecting CWI Trec cooling rates in men with hyperthermia; this has never been confirmed in women with hyperthermia. OBJECTIVE To examine whether the BSA:LBM ratio and other anthropometrics affect Trec cooling rates in women with hyperthermia. DESIGN Cross-sectional study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Sixteen women were placed in either a low BSA:LBM ratio (LOW; n = 8; age = 22 ± 1 years, height = 166.8 ± 6.0 cm, mass = 64.1 ± 4.5 kg, BSA:LBM ratio = 3.759 ± 0.214 m2/kg·102) or high BSA:LBM ratio group (HIGH; n = 8; age = 22 ± 2 years, height = 162.7 ± 8.9 cm, mass = 65.8 ± 12.7 kg, BSA:LBM ratio = 4.161 ± 0.232 m2/kg·102). INTERVENTION(S) On day 1, we measured physical characteristics using dual-energy x-ray absorptiometry, and participants completed a maximal oxygen consumption test. On day 2, participants walked at 4.8 km/h for 3 minutes and then ran at 80% of their predetermined maximal oxygen consumption for 2 minutes in the heat (temperature = ~40°C, relative humidity = 40%). This sequence was repeated until Trec reached 39.5°C. Then, they completed CWI (temperature = ~10°C) until Trec was 38°C. MAIN OUTCOME MEASURE(S) Rectal temperature and CWI cooling rates. RESULTS Groups had different BSA:LBM ratios (P = .001), body fat percentages (LOW: 25.7% ± 5.0%; HIGH: 33.7% ± 6.3%; P = .007), and LBM (LOW: 45.8 ± 3.0 kg; HIGH: 41.0 ± 5.1 kg; P = .02) but not different BSA (LOW: 1.72 ± 0.08 m2; HIGH: 1.70 ± 0.16 m2; P = .40) or BMI (LOW: 23.1 ± 2.1; HIGH: 24.9 ± 4.7; P = .17). Despite differences in several physical characteristics, Trec cooling rates were excellent but comparable (LOW: 0.26°C/min ± 0.09°C/min; HIGH: 0.27°C/min ± 0.07°C/min; P = .39). The BSA:LBM ratio (r = 0.14, P = .59), body fat percentage (r = 0.29, P = .28), LBM (r = -0.10, P = .70), BSA (r = -0.01, P = .97), and BMI (r = 0.37, P = .16) were not correlated with Trec cooling rates. CONCLUSIONS Body anthropometrics did not affect CWI Trec cooling rates in women with hyperthermia. Clinicians need not worry about anthropometric characteristics slowing the treatment of severe hyperthermia in women using CWI.
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Affiliation(s)
- Fallon S Koenig
- *School of Health Sciences, Central Michigan University, Mount Pleasant
| | - Kevin C Miller
- †School of Rehabilitation and Medical Sciences, Central Michigan University, Mount Pleasant
| | - Paul O'Connor
- *School of Health Sciences, Central Michigan University, Mount Pleasant
| | - Noshir Amaria
- ‡College of Medicine, Central Michigan University, Mount Pleasant
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Lipman GS, Gaudio FG, Eifling KP, Ellis MA, Otten EM, Grissom CK. Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Heat Illness: 2019 Update. Wilderness Environ Med 2019; 30:S33-S46. [DOI: 10.1016/j.wem.2018.10.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 09/04/2018] [Accepted: 10/22/2018] [Indexed: 10/26/2022]
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Does Gender Affect Rectal Temperature Cooling Rates? A Critically Appraised Topic. J Sport Rehabil 2019; 28:522-525. [DOI: 10.1123/jsr.2018-0081] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Effects of Intravenous Cold Saline on Hyperthermic Athletes Representative of Large Football Players and Small Endurance Runners. Clin J Sport Med 2018; 28:493-499. [PMID: 29112514 DOI: 10.1097/jsm.0000000000000505] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To evaluate the cooling effects of intravenous (IV) cold normal (0.9%) saline on hyperthermic athletes. DESIGN Randomized crossover study design. SETTING Controlled research laboratory. PARTICIPANTS Twelve male participants who were representative of a collegiate cross-country (6) and American football (6) population. INTERVENTIONS Participants underwent body composition analysis using a BodPod. They were placed in an environmentally controlled chamber and brought to a Tc of 39.5°C with dynamic exercise. When temperatures were reached, they were treated with either 2 L of cold saline (CS) (4°C) or intravenous room temperature (22°C) saline (RS) over a ∼30-minute period. Tre was measured with a rectal temperature probe every minute during the treatment period. MAIN OUTCOME MEASURES Total ΔTre (ending Tre - starting Tre) and cooling rate (total change in Tre/time) were measured for each condition, and body composition variables calculated included body surface area (BSA), BSA-to-mass ratio (BSA/mass), lean body mass, and body fat percentage (%BF) (P < 0.05). RESULTS Statistically significant differences were found in the total ΔTre and cooling rate between the CS and RS trials. The cooling rate for the CS trials was significantly correlated to mass, BSA, BSA/mass, and %BF. CONCLUSIONS In hyperthermic athletes, core temperature was reduced more effectively using chilled saline during IV infusion. Body composition had a significant impact on overall cooling revealing that the smaller and leaner participants cooled at a greater rate. When indicated, CS infusion could be considered for cooling hyperthermic individuals when other methods are not available.
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Abstract
Excised fat tissue has a lower thermal conductivity than excised lean tissue. In theory then subcutaneous fat might serve as a barrier to heat loss and influence thermoregulatory abilities. In some aquatic mammals and animals from severely cold habitats subcutaneous adipose tissue has evolved into a continuous sheet that envelopes the organs and acts as a thermal insulation layer. This layer can comprise more than half of the cross-sectional area of the body. In most mammals however, the distribution of fat is less continuous. It has been suggested that in tropical animals this distribution may in fact allow animals to still store energy while not impeding heat loss. Studies of humans immersed in cool water convincingly demonstrate that obesity in humans also serves an insulation function. Humans with obesity cool less rapidly and have to elevate their metabolism less significantly than lean individuals when immersed in water. Although obesity provides an advantage in cold conditions it conversely impedes heat loss and makes obese people susceptible to heat stress more than lean individuals. In small mammals like mice the role of subcutaneous (or intradermal) fat for providing thermal insulation is less clear. In theory variations in thermoregulatory capacity may allow individuals different capabilities to burn off excess consumption. Hence, thermoregulatory variations may cause obesity differences. Thermoregulatory capacity is related to ambient temperature. Yet, levels of obesity are only weakly related to ambient temperature and this effect disappears when confounding factors like poverty and race are taken into account. Hence we conclude that obesity may have a significant impact on thermoregulatory physiology, but the converse is much less likely.
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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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Miller KC, Hughes LE, Long BC, Adams WM, Casa DJ. Validity of Core Temperature Measurements at 3 Rectal Depths During Rest, Exercise, Cold-Water Immersion, and Recovery. J Athl Train 2017; 52:332-338. [PMID: 28207294 PMCID: PMC5402531 DOI: 10.4085/1062-6050-52.2.10] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT No evidence-based recommendation exists regarding how far clinicians should insert a rectal thermistor to obtain the most valid estimate of core temperature. Knowing the validity of temperatures at different rectal depths has implications for exertional heat-stroke (EHS) management. OBJECTIVE To determine whether rectal temperature (Trec) taken at 4 cm, 10 cm, or 15 cm from the anal sphincter provides the most valid estimate of core temperature (as determined by esophageal temperature [Teso]) during similar stressors an athlete with EHS may experience. DESIGN Cross-sectional study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Seventeen individuals (14 men, 3 women: age = 23 ± 2 years, mass = 79.7 ± 12.4 kg, height = 177.8 ± 9.8 cm, body fat = 9.4% ± 4.1%, body surface area = 1.97 ± 0.19 m2). INTERVENTION(S) Rectal temperatures taken at 4 cm, 10 cm, and 15 cm from the anal sphincter were compared with Teso during a 10-minute rest period; exercise until the participant's Teso reached 39.5°C; cold-water immersion (∼10°C) until all temperatures were ≤38°C; and a 30-minute postimmersion recovery period. The Teso and Trec were compared every minute during rest and recovery. Because exercise and cooling times varied, we compared temperatures at 10% intervals of total exercise and cooling durations for these periods. MAIN OUTCOME MEASURE(S) The Teso and Trec were used to calculate bias (ie, the difference in temperatures between sites). RESULTS Rectal depth affected bias (F2,24 = 6.8, P = .008). Bias at 4 cm (0.85°C ± 0.78°C) was higher than at 15 cm (0.65°C ± 0.68°C, P < .05) but not higher than at 10 cm (0.75°C ± 0.76°C, P > .05). Bias varied over time (F2,34 = 79.5, P < .001). Bias during rest (0.42°C ± 0.27°C), exercise (0.23°C ± 0.53°C), and recovery (0.65°C ± 0.35°C) was less than during cooling (1.72°C ± 0.65°C, P < .05). Bias during exercise was less than during postimmersion recovery (0.65°C ± 0.35°C, P < .05). CONCLUSIONS When EHS is suspected, clinicians should insert the flexible rectal thermistor to 15 cm (6 in) because it is the most valid depth. The low level of bias during exercise suggests Trec is valid for diagnosing hyperthermia. Rectal temperature is a better indicator of pelvic organ temperature during cold-water immersion than is Teso.
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Botonis PG, Geladas ND, Kounalakis SN, Cherouveim ED, Koskolou MD. Effects of menthol application on the skin during prolonged immersion in swimmers and controls. Scand J Med Sci Sports 2016; 27:1560-1568. [PMID: 27859725 DOI: 10.1111/sms.12799] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2016] [Indexed: 12/16/2022]
Abstract
We hypothesized that menthol application on the skin would enhance vasoconstriction of subjects immersed in cool water, which would reduce heat loss and rectal temperature (Tre) cooling rate. Furthermore, it was hypothesized that this effect would be greater in individuals acclimatized to immersion in 24 °C water, such as swimmers. Seven swimmers (SW) and seven physical education students (CON) cycled at 60% VO2 max until Tre attained 38 °C, and were then immediately immersed in stirred water maintained at 24 °C on two occasions: without (NM) and with (M; 4.6 g per 100 mL of water) whole-body skin application of menthol cream. Heart rate, Tre, proximal-distal skin temperature gradient, oxygen uptake (VO2 ), electromyographic activity (EMG), and thermal sensation were measured. Tre reduction was similar among SW and CON in NM and CON in M (-0.71±0.31 °C in average), while it was smaller for SW in M (-0.37±0.18 °C, P < 0.01). VO2 and heart rate were greater in M compared with NM condition (P = 0.01). SW in M exhibited a shift of the threshold for shivering, as reflected in increased VO2 and EMG activity, toward a higher Tre compared with the other trials. Menthol application on the skin before immersion reduces heat loss, but defends Tre decline more effectively in swimmers than in non-swimmers.
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Affiliation(s)
- P G Botonis
- Department of Sports Medicine and Biology of Exercise, School of Physical Education and Sports Science, University of Athens, Athens, Greece.,Department of Aquatic Sports, School of Physical Education and Sports Science, University of Athens, Athens, Greece
| | - N D Geladas
- Department of Sports Medicine and Biology of Exercise, School of Physical Education and Sports Science, University of Athens, Athens, Greece
| | - S N Kounalakis
- Department of Sports Medicine and Biology of Exercise, School of Physical Education and Sports Science, University of Athens, Athens, Greece
| | - E D Cherouveim
- Department of Sports Medicine and Biology of Exercise, School of Physical Education and Sports Science, University of Athens, Athens, Greece
| | - M D Koskolou
- Department of Sports Medicine and Biology of Exercise, School of Physical Education and Sports Science, University of Athens, Athens, Greece
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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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Friesen BJ, Carter MR, Poirier MP, Kenny GP. Water immersion in the treatment of exertional hyperthermia: physical determinants. Med Sci Sports Exerc 2015; 46:1727-35. [PMID: 24784433 DOI: 10.1249/mss.0000000000000292] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE We examined the effect of differences in body surface area-to-lean body mass ratio (AD/LBM) on core temperature cooling rates during cold water immersion (CWI, 2°C) and temperate water immersion (TWI, 26°C) after exercise-induced hyperthermia. METHODS Twenty male participants were divided into two groups: high (315.6 ± 7.9 cm·kg, n = 10) and low (275.6 ± 8.6 cm·kg, n = 10) AD/LBM. On two separate occasions, participants ran on a treadmill in the heat (40.0°C, 20% relative humidity) wearing an impermeable rain suit until rectal temperature reached 40.0°C. After exercise, participants were immersed up to the nipples (arms remained out of the water) in either a CWI (2°C) or a TWI (26°C) circulated water bath until rectal temperature returned to 37.5°C. RESULTS Overall rectal cooling rates were significantly different between experimental groups (high vs low AD/LBM, P = 0.005) and between immersion conditions (CWI vs TWI, P < 0.001). Individuals with a high AD/LBM had an approximately 1.7-fold greater overall rectal cooling rate relative to those with low AD/LBM during both CWI (high: 0.27°C·min ± 0.10°C·min vs low: 0.16°C·min ± 0.10°C·min) and TWI (high: 0.10°C·min ± 0.05°C·min vs low: 0.06°C·min ± 0.02°C·min). Further, the overall rectal cooling rates during CWI were approximately 2.7-fold greater than during TWI for both the high (CWI: 0.27°C·min ± 0.10°C·min vs TWI: 0.10°C·min ± 0.05°C·min) and the low (CWI: 0.16°C·min ± 0.10°C·min vs TWI: 0.06°C·min ± 0.02°C·min) AD/LBM groups. CONCLUSION We show that individuals with a low AD/LBM have a reduced rectal cooling rate and take longer to cool than those with a high AD/LBM during both CWI and TWI. However, CWI provides the most effective cooling treatment irrespective of physical differences.
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Affiliation(s)
- Brian J Friesen
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, CANADA
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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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Lipman GS, Eifling KP, Ellis MA, Gaudio FG, Otten EM, Grissom CK. Wilderness Medical Society practice guidelines for the prevention and treatment of heat-related illness: 2014 update. Wilderness Environ Med 2015; 25:S55-65. [PMID: 25498263 DOI: 10.1016/j.wem.2014.07.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 06/26/2014] [Accepted: 07/01/2014] [Indexed: 11/29/2022]
Abstract
The Wilderness Medical Society (WMS) convened an expert panel to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. We present a review of the classifications, pathophysiology, and evidence-based guidelines for planning and preventive measures as well as best practice recommendations for both field and hospital-based therapeutic management of heat illness. These recommendations are graded on the basis of the quality of supporting evidence, and balance between the benefits and risks or burdens for each modality. This is an updated version of the original WMS Practice Guidelines for the Prevention and Treatment of Heat-Related Illness published in Wilderness & Environmental Medicine 2013;24(4):351-361.
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Affiliation(s)
- Grant S Lipman
- Division of Emergency Medicine, Stanford University School of Medicine, Stanford, CA (Dr Lipman).
| | - Kurt P Eifling
- Division of Emergency Medicine, Barnes-Jewish Hospital/Washington University School of Medicine, Saint Louis, MO (Dr Eifling)
| | - Mark A Ellis
- Department of Emergency Medicine, Spartanburg Regional Healthcare System, Spartanburg, SC (Dr Eifling)
| | - Flavio G Gaudio
- Division of Emergency Medicine, New York-Presbyterian Hospital/Weill Cornell Medical College, New York, NY (Dr Gaudio)
| | - Edward M Otten
- Department of Emergency Medicine, University of Cincinnati, Cincinnati, OH (Dr Otten)
| | - Colin K Grissom
- Pulmonary and Critical Care Division, Intermountain Medical Center and the University of Utah, Salt Lake City, UT (Dr Grissom)
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Treatment of exertional heat stress developed during low or moderate physical work. Eur J Appl Physiol 2014; 114:2551-60. [PMID: 25118838 DOI: 10.1007/s00421-014-2971-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 07/28/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE We examined whether treatment for exertional heat stress via ice water immersion (IWI) or natural recovery is affected by the intensity of physical work performed and, thus, the time taken to reach hyperthermia. METHODS Nine adults (18-45 years; 17.9 ± 2.8 percent body fat; 57.0 ± 2.0 mL kg(-1) min(-1) peak oxygen uptake) completed four conditions incorporating either walking or jogging at 40 °C (20 % relative humidity) while wearing a non-permeable rain poncho. Upon reaching 39.5 °C rectal temperature (Tre), participants recovered either via IWI in 2 °C water or via natural recovery (seated in a ~29 °C environment) until T re returned to 38 °C. RESULTS Cooling rates were greater in the IWI [Tre: 0.24 °C min(-1); esophageal temperature (Tes): 0.24 °C min(-1)] than the natural recovery (Tre and Tes: 0.03 °C min(-1)) conditions (p < 0.001) with no differences between the two moderate and the two low intensity conditions (p > 0.05). Cooling rates for T re and T es were greater in the 39.0-38.5 °C (Tre: 0.19 °C min(-1); Tes: 0.31 °C min(-1)) compared with the 39.5-39.0 °C (Tre: 0.11 °C min(-1); Tes: 0.13 °C min(-1)) period across conditions (p < 0.05). Similar reductions in heart rate and mean arterial pressure were observed during recovery across conditions (p > 0.05), albeit occurred faster during IWI. Percent change in plasma volume at the end of natural recovery and IWI was 5.96 and 9.58%, respectively (p < 0.001). CONCLUSION The intensity of physical work performed and, thus, the time taken to reach hyperthermia does not affect the effectiveness of either IWI treatment or natural recovery. Therefore, while the path to hyperthermia may be different for each patient, the path to recovery must always be immediate IWI treatment.
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Versey NG, Halson SL, Dawson BT. Water immersion recovery for athletes: effect on exercise performance and practical recommendations. Sports Med 2014; 43:1101-30. [PMID: 23743793 DOI: 10.1007/s40279-013-0063-8] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Water immersion is increasingly being used by elite athletes seeking to minimize fatigue and accelerate post-exercise recovery. Accelerated short-term (hours to days) recovery may improve competition performance, allow greater training loads or enhance the effect of a given training load. However, the optimal water immersion protocols to assist short-term recovery of performance still remain unclear. This article will review the water immersion recovery protocols investigated in the literature, their effects on performance recovery, briefly outline the potential mechanisms involved and provide practical recommendations for their use by athletes. For the purposes of this review, water immersion has been divided into four techniques according to water temperature: cold water immersion (CWI; ≤20 °C), hot water immersion (HWI; ≥36 °C), contrast water therapy (CWT; alternating CWI and HWI) and thermoneutral water immersion (TWI; >20 to <36 °C). Numerous articles have reported that CWI can enhance recovery of performance in a variety of sports, with immersion in 10-15 °C water for 5-15 min duration appearing to be most effective at accelerating performance recovery. However, the optimal CWI duration may depend on the water temperature, and the time between CWI and the subsequent exercise bout appears to influence the effect on performance. The few studies examining the effect of post-exercise HWI on subsequent performance have reported conflicting findings; therefore the effect of HWI on performance recovery is unclear. CWT is most likely to enhance performance recovery when equal time is spent in hot and cold water, individual immersion durations are short (~1 min) and the total immersion duration is up to approximately 15 min. A dose-response relationship between CWT duration and recovery of exercise performance is unlikely to exist. Some articles that have reported CWT to not enhance performance recovery have had methodological issues, such as failing to detect a decrease in performance in control trials, not performing full-body immersion, or using hot showers instead of pools. TWI has been investigated as both a control to determine the effect of water temperature on performance recovery, and as an intervention itself. However, due to conflicting findings it is uncertain whether TWI improves recovery of subsequent exercise performance. Both CWI and CWT appear likely to assist recovery of exercise performance more than HWI and TWI; however, it is unclear which technique is most effective. While the literature on the use of water immersion for recovery of exercise performance is increasing, further research is required to obtain a more complete understanding of the effects on performance.
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Affiliation(s)
- Nathan G Versey
- Performance Recovery, Australian Institute of Sport, PO Box 176, Belconnen, Canberra, ACT, 2616, Australia,
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Lipman GS, Eifling KP, Ellis MA, Gaudio FG, Otten EM, Grissom CK. Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Heat-Related Illness. Wilderness Environ Med 2013; 24:351-61. [DOI: 10.1016/j.wem.2013.07.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 07/09/2013] [Accepted: 07/09/2013] [Indexed: 11/16/2022]
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Lemire BB, Gagnon D, Jay O, Kenny GP. Differences between sexes in rectal cooling rates after exercise-induced hyperthermia. Med Sci Sports Exerc 2009; 41:1633-9. [PMID: 19568196 DOI: 10.1249/mss.0b013e31819e010c] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE We evaluated differences between sexes in core cooling rates during cold water immersion after exercise-induced hyperthermia. METHODS Ten male (M) and nine female (F) participants, matched for body surface area-to-mass ratio (AD/M) (F: 268 +/- 19 vs M: 261 +/- 16 cm2 x kg(-1)), were recruited for the study. Participants exercised until rectal temperature reached 39.5 degrees C and were subsequently immersed in a 2.0 degrees C circulated water bath until rectal temperature decreased to 37.5 degrees C. Rectal and mean skin temperatures and the relative rate of nonevaporative heat loss (W x m(-2)) were measured continuously during the immersion period. RESULTS Males were heavier, had a lower body fat percentage, and had a greater amount of lean body mass compared with females (P < or = 0.05). Significant differences were found in the overall cooling rate for rectal temperature (F: 0.22 +/- 0.07 vs M: 0.12 +/- 0.03 degrees C x min(-1), P = 0.001) and in the overall immersion times (F: 10.89 +/- 4.49 vs M: 18.13 +/- 4.47 min, P = 0.003). Mean skin temperature was lower in females compared with that in males during the immersion period (P < 0.001), although there were no differences between sexes in the rate of nonevaporative heat loss (P = 0.180). CONCLUSIONS Although females had a similar AD/M and greater body adiposity, they had approximately 1.7-fold greater rectal cooling rate. Because AD/M and body adiposity do not seem to influence rectal cooling rates in previously hyperthermic individuals, the greater cooling rates in females may be attributed to physical differences in lean body mass.
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Affiliation(s)
- Bruno B Lemire
- Laboratory of Human Bioenergetics and Environmental Physiology, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
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