scholarly journals Cold-Water Immersion for Hyperthermic Humans Wearing American Football Uniforms

2015 ◽  
Vol 50 (8) ◽  
pp. 792-799 ◽  
Author(s):  
Kevin C. Miller ◽  
Erik E. Swartz ◽  
Blaine C. Long
Keyword(s):  
Effect Size ◽  
Cold Water ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Current Treatment ◽  
The Body ◽  
American Football ◽  
Cooling Rates ◽  
Physically Active ◽  
Core Cooling

Context Current treatment recommendations for American football players with exertional heatstroke are to remove clothing and equipment and immerse the body in cold water. It is unknown if wearing a full American football uniform during cold-water immersion (CWI) impairs rectal temperature (Trec) cooling or exacerbates hypothermic afterdrop. Objective To determine the time to cool Trec from 39.5°C to 38.0°C while participants wore a full American football uniform or control uniform during CWI and to determine the uniform's effect on Trec recovery postimmersion. Design Crossover study. Setting Laboratory. Patients or Other Participants A total of 18 hydrated, physically active, unacclimated men (age = 22 ± 3 years, height = 178.8 ± 6.8 cm, mass = 82.3 ± 12.6 kg, body fat = 13% ± 4%, body surface area = 2.0 ± 0.2 m2). Intervention(s) Participants wore the control uniform (undergarments, shorts, crew socks, tennis shoes) or full uniform (control plus T-shirt; tennis shoes; jersey; game pants; padding over knees, thighs, and tailbone; helmet; and shoulder pads). They exercised (temperature approximately 40°C, relative humidity approximately 35%) until Trec reached 39.5°C. They removed their T-shirts and shoes and were then immersed in water (approximately 10°C) while wearing each uniform configuration; time to cool Trec to 38.0°C (in minutes) was recorded. We measured Trec (°C) every 5 minutes for 30 minutes after immersion. Main Outcome Measure(s) Time to cool from 39.5°C to 38.0°C and Trec. Results The Trec cooled to 38.0°C in 6.19 ± 2.02 minutes in full uniform and 8.49 ± 4.78 minutes in control uniform (t17 = −2.1, P = .03; effect size = 0.48) corresponding to cooling rates of 0.28°C·min−1 ± 0.12°C·min−1 in full uniform and 0.23°C·min−1 ± 0.11°C·min−1 in control uniform (t17 = 1.6, P = .07, effect size = 0.44). The Trec postimmersion recovery did not differ between conditions over time (F1,17 = 0.6, P = .59). Conclusions We speculate that higher skin temperatures before CWI, less shivering, and greater conductive cooling explained the faster cooling in full uniform. Cooling rates were considered ideal when the full uniform was worn during CWI, and wearing the full uniform did not cause a greater postimmersion hypothermic afterdrop. Clinicians may immerse football athletes with hyperthermia wearing a full uniform without concern for negatively affecting body-core cooling.

Effect of alcohol on thermal balance of man in cold water

1979 ◽  
Vol 57 (8) ◽  
pp. 860-865 ◽  
Author(s):  
G. R. Fox ◽  
J. S. Hayward ◽  
G. N. Hobson
Keyword(s):  
Metabolic Rate ◽  
Cold Water ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Cooling Rates ◽  
Rate Of Increase ◽  
Exercise Period ◽  
Hot Bath ◽  
Core Cooling ◽  
Skin Temperatures

The effects of alcohol on core cooling rates (rectal and tympanic), skin temperatures, and metabolic rate were determined for 10 subjects rendered hypothermic by immersion for 45 min in 10 °C water. Experiments were duplicated with and without a 20-min period of exercise at the beginning of cold water immersion. Measurements were continued during rewarming in a hot bath. With blood alcohol concentrations averaging 82 mg 100 mL−1, core cooling rates and changes in skin temperatures were insignificantly different from controls, even if the exercise period was imposed. Alcohol reduced shivering metabolic rate by an overall mean of 13%, insufficient to affect cooling rate. Alcohol had no effect on metabolic rate during exercise. During rewarming by hot bath, the amount of 'afterdrop' and rate of increase in core temperature were unaffected by alcohol. It was concluded that alcohol in a moderate dosage does not influence the rate of progress into hypothermia or subsequent, efficient rewarming. This emphasizes that the high incidence of alcohol involvement in water-related fatalities is due to alcohol potentiation of accidents rather than any direct effects on cold water survival, although very high doses of alcohol leading to unconsciousness would increase rate of progress into hypothermia.

scholarly journals Temperate-Water Immersion as a Treatment for Hyperthermic Humans Wearing American Football Uniforms

2017 ◽  
Vol 52 (8) ◽  
pp. 747-752 ◽  
Author(s):  
Kevin C. Miller ◽  
Tyler Truxton ◽  
Blaine Long
Keyword(s):  
Rectal Temperature ◽  
Cold Water ◽  
Thermal Sensation ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
American Football ◽  
Body Core Temperature ◽  
Temperate Water ◽  
Cooling Rates ◽  
Before And After

Context:  Cold-water immersion (CWI; 10°C) can effectively reduce body core temperature even if a hyperthermic human is wearing a full American football uniform (PADS) during treatment. Temperate-water immersion (TWI; 21°C) may be an effective alternative to CWI if resources for the latter (eg, ice) are unavailable. Objective:  To measure rectal temperature (Trec) cooling rates, thermal sensation, and Environmental Symptoms Questionnaire (ESQ) scores of participants wearing PADS or shorts, undergarments, and socks (NOpads) before, during, and after TWI. Design:  Crossover study. Setting:  Laboratory. Patients or Other Participants:  Thirteen physically active, unacclimatized men (age = 22 ± 2 years, height = 182.3 ± 5.2 cm, mass = 82.5 ± 13.4 kg, body fat = 10% ± 4%, body surface area = 2.04 ± 0.16 m2). Intervention(s):  Participants exercised in the heat (40°C, 50% relative humidity) on 2 days while wearing PADS until Trec reached 39.5°C. Participants then underwent TWI while wearing either NOpads or PADS until Trec reached 38°C. Thermal sensation and ESQ responses were collected at various times before and after exercise. Main Outcome Measure(s):  Temperate-water immersion duration (minutes), Trec cooling rates (°C/min), thermal sensation, and ESQ scores. Results:  Participants had similar exercise times (NOpads = 38.1 ± 8.1 minutes, PADS = 38.1 ± 8.5 minutes), hypohydration levels (NOpads = 1.1% ± 0.2%, PADS = 1.2% ± 0.2%), and thermal sensation ratings (NOpads = 7.1 ± 0.4, PADS = 7.3 ± 0.4) before TWI. Rectal temperature cooling rates were similar between conditions (NOpads = 0.12°C/min ± 0.05°C/min, PADS = 0.13°C/min ± 0.05°C/min; t12 = 0.82, P = .79). Thermal sensation and ESQ scores were unremarkable between conditions over time. Conclusions:  Temperate-water immersion produced acceptable (ie, >0.08°C/min), though not ideal, cooling rates regardless of whether PADS or NOpads were worn. If a football uniform is difficult to remove or the patient is noncompliant, clinicians should begin water-immersion treatment with the athlete fully equipped. Clinicians should strive to use CWI to treat severe hyperthermia, but when CWI is not feasible, TWI should be the next treatment option because its cooling rate was higher than the rates of other common modalities (eg, ice packs, fanning).

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 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.

scholarly journals Precooling, Hyperthermia, and Postexercise Cooling Rates in Humans Wearing American Football Uniforms

2019 ◽  
Vol 54 (7) ◽  
pp. 758-764 ◽  
Author(s):  
Jeremy Taylor ◽  
Kevin C. Miller
Keyword(s):  
Heart Rate ◽  
Rectal Temperature ◽  
Cold Water ◽  
Thermal Sensation ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Rating Of Perceived Exertion ◽  
American Football ◽  
Whole Body ◽  
Cooling Rates

Context Exertional heatstroke is one of the leading causes of death in American football players. Precooling (PC) with whole-body cold-water immersion (CWI) may prevent severe hyperthermia and, possibly, exertional heatstroke. However, it is unknown how much PC delays severe hyperthermia when participants wear American football uniforms during exercise in the heat. Does PC alter the effectiveness of CWI once participants become hyperthermic or affect perceptual variables during exercise? Objectives We asked 3 questions: (1) Does PC affect how quickly participants become hyperthermic during exercise in the heat? (2) Does PC before exercise affect rectal temperature (Trec) cooling rates once participants become hyperthermic? (3) Does PC affect perceptual variables such as rating of perceived exertion (RPE), thermal sensation, and environmental symptoms questionnaire (ESQ) responses? Design Crossover study. Setting Laboratory. Patients or Other Participants Twelve physically active males (age = 24 ± 4 years, height = 181.8 ± 8.4 cm, mass = 79.9 ± 10.3 kg). Intervention(s) On PC days, participants completed 15 minutes of CWI (9.98°C ± 0.04°C). They donned American football uniforms and exercised in the heat (temperature = 39.1°C ± 0.3°C, relative humidity = 36% ± 2%) until Trec was 39.5°C. While wearing equipment, they then underwent CWI until Trec was 38°C. Control-day procedures were the same except for the PC intervention. Main Outcome Measure(s) Rectal temperature, heart rate, thermal sensation, RPE, and ESQ responses were measured throughout testing. The duration of cold-water immersion was used in conjunction with Trec to calculate cooling rates. Results Precooling allowed participants to exercise 17.6 ± 3.6 minutes longer before reaching 39.5°C (t11 = 17.0, P < .001). Precooling did not affect postexercise CWI Trec cooling rates (PC = 0.18°C/min ± 0.06°C/min, control = 0.20°C/min ± 0.09°C/min; t11 = 0.9, P = .17); ESQ responses (F2,24 = 1.3, P = .3); or RPE (F2,22 = 2.9, P = .07). Precooling temporarily lowered thermal sensation (F3,26 = 21.7, P < .001) and heart rate (F3,29 = 21.0, P < .001) during exercise. Conclusions Because PC delayed hyperthermia without negatively affecting perceptual variables or CWI effectiveness, clinicians may consider implementing PC along with other proven strategies for preventing heat illness (eg, acclimatization).

Heat balance precedes stabilization of body temperatures during cold water immersion

2003 ◽  
Vol 95 (1) ◽  
pp. 89-96 ◽  
Author(s):  
Peter Tikuisis
Keyword(s):  
Heat Balance ◽  
Cold Water ◽  
Water Immersion ◽  
Heat Content ◽  
Cold Water Immersion ◽  
The Body ◽  
Body Temperatures ◽  
Mean Body Temperature ◽  
The Core ◽  
Region Temperature

Certain previous studies suggest, as hypothesized herein, that heat balance (i.e., when heat loss is matched by heat production) is attained before stabilization of body temperatures during cold exposure. This phenomenon is explained through a theoretical analysis of heat distribution in the body applied to an experiment involving cold water immersion. Six healthy and fit men (mean ± SD of age = 37.5 ± 6.5 yr, height = 1.79 ± 0.07 m, mass = 81.8 ± 9.5 kg, body fat = 17.3 ± 4.2%, maximal O2 uptake = 46.9 ± 5.5 l/min) were immersed in water ranging from 16.4 to 24.1°C for up to 10 h. Core temperature (Tco) underwent an insignificant transient rise during the first hour of immersion, then declined steadily for several hours, although no subject's Tco reached 35°C. Despite the continued decrease in Tco, shivering had reached a steady state of ∼2 × resting metabolism. Heat debt peaked at 932 ± 334 kJ after 2 h of immersion, indicating the attainment of heat balance, but unexpectedly proceeded to decline at ∼48 kJ/h, indicating a recovery of mean body temperature. These observations were rationalized by introducing a third compartment of the body, comprising fat, connective tissue, muscle, and bone, between the core (viscera and vessels) and skin. Temperature change in this “mid region” can account for the incongruity between the body's heat debt and the changes in only the core and skin temperatures. The mid region temperature decreased by 3.7 ± 1.1°C at maximal heat debt and increased slowly thereafter. The reversal in heat debt might help explain why shivering drive failed to respond to a continued decrease in Tco, as shivering drive might be modulated by changes in body heat content.

scholarly journals Cooling Effectiveness of a Modified Cold-Water Immersion Method After Exercise-Induced Hyperthermia

2016 ◽  
Vol 51 (11) ◽  
pp. 946-951 ◽  
Author(s):  
Katherine E. Luhring ◽  
Cory L. Butts ◽  
Cody R. Smith ◽  
Jeffrey A. Bonacci ◽  
Ramon C. Ylanan ◽  
...  
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Effect Size ◽  
Cold Water ◽  
Water Immersion ◽  
Heat Stroke ◽  
Cold Water Immersion ◽  
Whole Body ◽  
Exertional Heat Stroke

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.

Effect of nifedipine on core cooling in rats during tail cold water immersion

2003 ◽  
Vol 28 (8) ◽  
pp. 551-554
Author(s):  
Michael J. Durkot ◽  
Lawrence de Garavilla
Keyword(s):  
Cold Water ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Core Cooling

scholarly journals Cold-Water Immersion Cooling Rates in Football Linemen and Cross-Country Runners With Exercise-Induced Hyperthermia

2017 ◽  
Vol 52 (10) ◽  
pp. 902-909 ◽  
Author(s):  
Sandra Fowkes Godek ◽  
Katherine E. Morrison ◽  
Gregory Scullin
Keyword(s):  
Cooling Rate ◽  
Body Mass ◽  
Body Fat ◽  
Cold Water ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Physical Characteristics ◽  
Cooling Rates ◽  
Cross Country ◽  
Cross Country Runners

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.

scholarly journals Optimizing Cold-Water Immersion for Exercise-Induced Hyperthermia: An Evidence-Based Paper

2016 ◽  
Vol 51 (6) ◽  
pp. 500-501 ◽  
Author(s):  
Emma A. Nye ◽  
Jessica R. Edler ◽  
Lindsey E. Eberman ◽  
Kenneth E. Games
Keyword(s):  
Ambient Temperature ◽  
Water Temperature ◽  
Core Temperature ◽  
Cold Water ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Cooling Rates ◽  
Induced Hyperthermia ◽  
Passive Recovery ◽  
Exercise Induced

Reference: Zhang Y, Davis JK, Casa DJ, Bishop PA. Optimizing cold water immersion for exercise-induced hyperthermia: a meta-analysis. Med Sci Sports Exerc. 2015;47(11):2464−2472. Clinical Questions: Do optimal procedures exist for implementing cold-water immersion (CWI) that yields high cooling rates for hyperthermic individuals? Data Sources: One reviewer performed a literature search using PubMed and Web of Science. Search phrases were cold water immersion, forearm immersion, ice bath, ice water immersion, immersion, AND cooling. Study Selection: Studies were included based on the following criteria: (1) English language, (2) full-length articles published in peer-reviewed journals, (3) healthy adults subjected to exercise-induced hyperthermia, and (4) reporting of core temperature as 1 outcome measure. A total of 19 studies were analyzed. Data Extraction: Pre-immersion core temperature, immersion water temperature, ambient temperature, immersion duration, and immersion level were coded a priori for extraction. Data originally reported in graphical form were digitally converted to numeric values. Mean differences comparing the cooling rates of CWI with passive recovery, standard deviation of change from baseline core temperature, and within-subjects r were extracted. Two independent reviewers used the Physiotherapy Evidence Database (PEDro) scale to assess the risk of bias. Main Results: Cold-water immersion increased the cooling rate by 0.03°C/min (95% confidence interval [CI] = 0.03, 0.04°C/min) compared with passive recovery. Cooling rates were more effective when the pre-immersion core temperature was ≥38.6°C (P = .023), immersion water temperature was ≤10°C (P = .036), ambient temperature was ≥20°C (P = .013), or immersion duration was ≤10 minutes (P < .001). Cooling rates for torso and limb immersion (mean difference = 0.04°C/min, 95% CI = 0.03, 0.06°C/min) were higher (P = .028) than those for forearm and hand immersion (mean difference = 0.01°C/min, 95% CI = −0.01, 0.04°C/min). Conclusions: Hyperthermic individuals were cooled twice as fast by CWI as by passive recovery. Therefore, the former method is the preferred choice when treating patients with exertional heat stroke. Water temperature should be <10°C, with the torso and limbs immersed. Insufficient published evidence supports CWI of the forearms and hands.

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