Int J Sports Med 2012; 33(11): 859-866
DOI: 10.1055/s-0032-1304643
Physiology & Biochemistry
© Georg Thieme Verlag KG Stuttgart · New York

Ice Slurry on Outdoor Running Performance in Heat

Z. W. Yeo
1  Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore
,
P.W. P. Fan
2  Defence Medical & Environmental Research Institute, DSO National Laboratories, Military Physiology Laboratory, Singapore
,
A.Q. X. Nio
2  Defence Medical & Environmental Research Institute, DSO National Laboratories, Military Physiology Laboratory, Singapore
,
C. Byrne
3  School of Sport and Health Sciences, University of Exeter, United Kingdom
,
J.K. W. Lee
2  Defence Medical & Environmental Research Institute, DSO National Laboratories, Military Physiology Laboratory, Singapore
› Author Affiliations
Further Information

Publication History



accepted after revision 31 January 2012

Publication Date:
22 June 2012 (online)

Abstract

The efficacy of ingestion of ice slurry on actual outdoor endurance performance is unknown. This study aimed to investigate ice slurry ingestion as a cooling intervention before a 10 km outdoor running time-trial. Twelve participants ingested 8 g · kg − 1 of either ice slurry ( − 1.4°C; ICE) or ambient temperature drink (30.9°C; CON) and performed a 15-min warm-up prior to a 10 km outdoor running time-trial (Wet Bulb Globe Temperature: 28.2±0.8°C). Mean performance time was faster with ICE (2 715±396 s) than CON (2 730±385 s; P=0.023). Gastrointestinal temperature (Tgi) reduced by 0.5±0.2°C after ICE ingestion compared with 0.1±0.1°C (P<0.001) with CON. During the run, the rate of rise in Tgi was greater (P=0.01) with ICE than with CON for the first 15 min. At the end of time-trial, Tgi was higher with ICE (40.2±0.6°C) than CON (39.8±0.4°C, P=0.005). Ratings of thermal sensation were lower during the cooling phase and for the first kilometre of the run ( − 1.2±0.8; P<0.001). Although ingestion of ice slurry resulted in a transient increase in heat strain following a warm up routine, it is a practical and effective pre-competition cooling manoeuvre to improve performance in warm and humid environments.