Brief in-play cooling breaks reduce thermal strain during football in hot conditions

Samuel Chalmers; Jason Siegler; Ric Lovell; Grant Lynch; Warren Gregson; Paul Marshall; Ollie Jay

doi:10.1016/j.jsams.2019.04.009

Brief in-play cooling breaks reduce thermal strain during football in hot conditions

J Sci Med Sport. 2019 Aug;22(8):912-917. doi: 10.1016/j.jsams.2019.04.009. Epub 2019 May 4.

Authors

Samuel Chalmers¹, Jason Siegler², Ric Lovell², Grant Lynch³, Warren Gregson⁴, Paul Marshall², Ollie Jay⁵

Affiliations

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.

PMID: 31151878
DOI: 10.1016/j.jsams.2019.04.009

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 (COOL_water), 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 (COOL_towel), regular simulated match with an extended (+5 min; total of 20-min) half-time break (HT_extended).

Results: The difference in rectal temperature change was significantly lower in the COOL_water (-0.25 °C), COOL_towel (-0.28 °C), and HT_extended (-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 COOL_water (-13 bpm; -1.4 au), COOL_towel (-10 bpm; -1.3 au), and HT_extended (-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.

Keywords: Body temperature regulation; Heat stress; Hot temperature; Soccer; Sports.

MeSH terms

Body Temperature Regulation / physiology*
Cryotherapy / methods*
Football / physiology*
Heat Stress Disorders / prevention & control*
Hot Temperature / adverse effects*
Humans
Male
Physical Exertion / physiology*
Rest / physiology
Water
Young Adult

Substances

Water