Samuel Chalmers1, Jason Siegler2, Ric Lovell2, Grant Lynch3, Warren Gregson4, Paul Marshall2, Ollie Jay5. 1. Sport and Exercise Science, School of Science and Health, Western Sydney University, Australia; Thermal Ergonomics Laboratory, Faculty of Health Sciences, The University of Sydney, Australia. 2. Sport and Exercise Science, School of Science and Health, Western Sydney University, Australia. 3. Thermal Ergonomics Laboratory, Faculty of Health Sciences, The University of Sydney, Australia. 4. Aspire Academy, Qatar; Football Exchange, Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, UK. 5. Thermal Ergonomics Laboratory, Faculty of Health Sciences, The University of Sydney, Australia; Charles Perkins Centre, The University of Sydney, Australia. Electronic address: ollie.jay@sydney.edu.au.
Abstract
OBJECTIVES: The study examined if three feasible strategies involving additional in-play cooling periods attenuate the core (rectal) temperature rise during simulated football matches. DESIGN: Four counterbalanced experimental trials in an environmental chamber set to 35 °C ambient temperature, 55% relative humidity, and 30 °C WBGT. METHODS: Twelve healthy well-trained football players completed a regular simulated match (REG), regular simulated match with additional 3-min cooling periods at the 30-min mark of each half inclusive of chilled water consumption (COOLwater), regular simulated match with additional 3-min cooling periods at the 30-min mark of each half inclusive of chilled water consumption and the application of an ice towel around the neck (COOLtowel), regular simulated match with an extended (+5 min; total of 20-min) half-time break (HTextended). RESULTS: The difference in rectal temperature change was significantly lower in the COOLwater (-0.25 °C), COOLtowel (-0.28 °C), and HTextended (-0.21 °C) trials in comparison to the REG (all p < 0.05). Exercising heart rate and session rating of perceived exertion was lower in the COOLwater (-13 bpm; -1.4 au), COOLtowel (-10 bpm; -1.3 au), and HTextended (-8 bpm; -0.9 au) trials in comparison to the REG trial (all p < 0.05). The cooling interventions did not significantly change skin temperature or thermal sensation in comparison to the REG (all p > 0.05). CONCLUSIONS: All three cooling interventions attenuated core body thermal strain during simulated matches. The laboratory-based study supports the use of brief in-play cooling periods as a means to attenuate the rise in core temperature during matches in hot and humid conditions.
OBJECTIVES: The study examined if three feasible strategies involving additional in-play cooling periods attenuate the core (rectal) temperature rise during simulated football matches. DESIGN: Four counterbalanced experimental trials in an environmental chamber set to 35 °C ambient temperature, 55% relative humidity, and 30 °C WBGT. METHODS: Twelve healthy well-trained football players completed a regular simulated match (REG), regular simulated match with additional 3-min cooling periods at the 30-min mark of each half inclusive of chilled water consumption (COOLwater), regular simulated match with additional 3-min cooling periods at the 30-min mark of each half inclusive of chilled water consumption and the application of an ice towel around the neck (COOLtowel), regular simulated match with an extended (+5 min; total of 20-min) half-time break (HTextended). RESULTS: The difference in rectal temperature change was significantly lower in the COOLwater (-0.25 °C), COOLtowel (-0.28 °C), and HTextended (-0.21 °C) trials in comparison to the REG (all p < 0.05). Exercising heart rate and session rating of perceived exertion was lower in the COOLwater (-13 bpm; -1.4 au), COOLtowel (-10 bpm; -1.3 au), and HTextended (-8 bpm; -0.9 au) trials in comparison to the REG trial (all p < 0.05). The cooling interventions did not significantly change skin temperature or thermal sensation in comparison to the REG (all p > 0.05). CONCLUSIONS: All three cooling interventions attenuated core body thermal strain during simulated matches. The laboratory-based study supports the use of brief in-play cooling periods as a means to attenuate the rise in core temperature during matches in hot and humid conditions.