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

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.

Proper Recognition and Management of Exertional Heat Stroke in a High School Cross Country Runner: A Validation Clinical Case Report

“…1 EHS is defined as a neuropsychiatric impairment with a high core temperature, usually > 40.5C (105.F) that can result in permanent disability or death if not properly treated. [2][3][4][5][6][7] Survival from EHS relies on proper recognition of EHS by obtaining a core body temperature and assessing for central nervous system (CNS) dysfunction and prompt aggressive cooling on site. 1,3,8,9 When EHS is recognized and treated within 30 minutes of collapse, death from EHS is preventable.…”

Cooling therapy upregulates protein C activation in heat stressed rats: An experimental study

“…Few studies compared the different temperature of cooling blanket in a single study. In 2002's study, ice-water immersion (5.15 ± 0.20°C), cold-water immersion (14.03 ± 0.28°C) were compared and no significant differences exist during the 12 min immersion, but significant differences were found 6 to 10 min postimmersion (Clements et al, 2002). Whether ice-water blanket produces superior cooling rates were unknown.…”

ACSM Expert Consensus Statement on Exertional Heat Illness: Recognition, Management, and Return to Activity

“…Cold water immersion has effective cooling rates with good clinical outcomes in EHS casualties and the preferred cooling strategy (47,56,63,64,70,71,74,75).…”