Pearl M S Tan1, Eunice Y N Teo1, Noreffendy B Ali2, Bryan C H Ang2,3, Iswady Iskandar2, Lydia Y L Law1, Jason K W Lee1,4. 1. Combat Protection and Performance, Defence Medical and Environmental Research Institute, Singapore. 2. Soldier Performance Centre, Singapore Armed Forces. 3. National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore. 4. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
Abstract
CONTEXT: Rapid diagnosis and expeditious cooling of individuals with exertional heat stroke is paramount for survival. OBJECTIVE: To evaluate the efficacy of various cooling systems after exercise-induced hyperthermia. DESIGN: Crossover study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-two men (age = 24 ± 2 years, height = 1.76 ± 0.07 m, mass = 70.7 ± 9.5 kg) participated. INTERVENTION(S): Each participant completed a treadmill walk until body core temperature reached 39.50°C. The treadmill walk was performed at 5.3 km/h on an 8.5% incline for 50 minutes and then at 5.0 km/h until the end of exercise. Each participant experienced 4 cooling phases in a randomized, repeated-crossover design: (1) no cooling (CON), (2) body-cooling unit (BCU), (3) EMCOOLS Flex.Pad (EC), and (4) ThermoSuit (TS). Cooling continued for 30 minutes or until body core temperature reached 38.00°C, whichever occurred earlier. MAIN OUTCOME MEASURE(S): Body core temperature (obtained via an ingestible telemetric temperature sensor) and heart rate were measured continuously during the exercise and cooling phases. Rating of perceived exertion was monitored every 5 minutes during the exercise phase and thermal sensation every minute during the cooling phase. RESULTS: The absolute cooling rate was greatest with TS (0.16°C/min ± 0.06°C/min) followed by EC (0.12°C/min ± 0.04°C/min), BCU (0.09°C/min ± 0.06°C/min), and CON (0.06°C/min ± 0.02°C/min; P < .001). The TS offered a greater cooling rate than all other cooling modalities in this study, whereas EC offered a greater cooling rate than both CON and BCU (P < .0083 for all). Effect-size calculations, however, showed that EC and BCU were not clinically different. CONCLUSION: These findings provide objective evidence for selecting the most effective cooling system of those we evaluated for cooling individuals with exercise-induced hyperthermia. Nevertheless, factors other than cooling efficacy need to be considered when selecting an appropriate cooling system.
RCT Entities:
CONTEXT: Rapid diagnosis and expeditious cooling of individuals with exertional heat stroke is paramount for survival. OBJECTIVE: To evaluate the efficacy of various cooling systems after exercise-induced hyperthermia. DESIGN: Crossover study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-two men (age = 24 ± 2 years, height = 1.76 ± 0.07 m, mass = 70.7 ± 9.5 kg) participated. INTERVENTION(S): Each participant completed a treadmill walk until body core temperature reached 39.50°C. The treadmill walk was performed at 5.3 km/h on an 8.5% incline for 50 minutes and then at 5.0 km/h until the end of exercise. Each participant experienced 4 cooling phases in a randomized, repeated-crossover design: (1) no cooling (CON), (2) body-cooling unit (BCU), (3) EMCOOLS Flex.Pad (EC), and (4) ThermoSuit (TS). Cooling continued for 30 minutes or until body core temperature reached 38.00°C, whichever occurred earlier. MAIN OUTCOME MEASURE(S): Body core temperature (obtained via an ingestible telemetric temperature sensor) and heart rate were measured continuously during the exercise and cooling phases. Rating of perceived exertion was monitored every 5 minutes during the exercise phase and thermal sensation every minute during the cooling phase. RESULTS: The absolute cooling rate was greatest with TS (0.16°C/min ± 0.06°C/min) followed by EC (0.12°C/min ± 0.04°C/min), BCU (0.09°C/min ± 0.06°C/min), and CON (0.06°C/min ± 0.02°C/min; P < .001). The TS offered a greater cooling rate than all other cooling modalities in this study, whereas EC offered a greater cooling rate than both CON and BCU (P < .0083 for all). Effect-size calculations, however, showed that EC and BCU were not clinically different. CONCLUSION: These findings provide objective evidence for selecting the most effective cooling system of those we evaluated for cooling individuals with exercise-induced hyperthermia. Nevertheless, factors other than cooling efficacy need to be considered when selecting an appropriate cooling system.
Authors: Gregory S Farnell; Katie E Pierce; Tiffany A Collinsworth; Leigh K Murray; Rob N Demes; Judi A Juvancic-Heltzel; Ellen L Glickman Journal: Wilderness Environ Med Date: 2008 Impact factor: 1.518
Authors: Lawrence E Armstrong; Amy C Pumerantz; Kelly A Fiala; Melissa W Roti; Stavros A Kavouras; Douglas J Casa; Carl M Maresh Journal: Int J Sport Nutr Exerc Metab Date: 2010-04 Impact factor: 4.599
Authors: Stephanie M Mazerolle; Ian C Scruggs; Douglas J Casa; Laura J Burton; Brendon P McDermott; Lawrence E Armstrong; Carl M Maresh Journal: J Athl Train Date: 2010 Mar-Apr Impact factor: 2.860
Authors: Abderrezak Bouchama; Bisher Abuyassin; Cynthia Lehe; Orlando Laitano; Ollie Jay; Francis G O'Connor; Lisa R Leon Journal: Nat Rev Dis Primers Date: 2022-02-03 Impact factor: 52.329
Authors: Julia Koehn; Ruihao Wang; Carmen de Rojas Leal; Bernd Kallmünzer; Klemens Winder; Martin Köhrmann; Rainer Kollmar; Stefan Schwab; Max J Hilz Journal: Neurol Sci Date: 2020-03-26 Impact factor: 3.307