title: The Effects of Crushed Ice Ingestion Prior to Steady State Exercise in the Heat.
abstract: This study examined the physiological effects of crushed ice ingestion before steady state exercise in the heat. Ten healthy males with age (23 ± 3 y), height (176.9 ± 8.7 cm), body-mass (73.5 ± 8.0 kg), VO2peak(48.5 ± 3.6 mL∙kg∙min-1) participated in the study. Participants completed 60 min of cycling at 55% of their VO2peakpreceded by 30 min of precooling whereby 7 g∙kg-1of thermoneutral water (CON) or crushed ice (ICE) was ingested. The reduction in Tcat the conclusion of precooling was greater in ICE (-0.9 ± 0.3 °C) compared with CON (-0.2 ± 0.2 °C) (p ≤ .05). Heat storage capacity was greater in ICE compared with CON after precooling (ICE -29.3 ± 4.8 W∙m-2; CON -11.1 ± 7.3 W∙m-2, p < .05). Total heat storage was greater in ICE compared with CON at the end of the steady state cycle (ICE 62.0 ± 12.5 W∙m-2; CON 49.9 ± 13.4 W∙m-2, p < .05). Gross efficiency was higher in ICE compared with CON throughout the steady state cycle (ICE 21.4 ± 1.8%; CON 20.4 ± 1.9%, p < .05). Ice ingestion resulted in a lower thermal sensation at the end of precooling and a lower sweat rate during the initial stages of cycling (p < .05). Sweat loss, respiratory exchange ratio, heart rate and ratings of perceived exertion and thirst were similar between conditions (p > .05). Precooling with crushed ice led to improved gross efficiency while cycling due to an increased heat storage capacity, which was the result of a lower core temperature.
authors.forename: Matthew
authors.initials: M
authors.lastname: Zimmermann
authors.forename: Grant
authors.initials: G
authors.lastname: Landers
authors.forename: Karen E
authors.initials: KE
authors.lastname: Wallman
authors.forename: Jacinta
authors.initials: J
authors.lastname: Saldaris
mesh_terms: D000328:Adult; D001642:Bicycling; D001831:Body Temperature; D004326:Drinking; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate; D006358:Hot Temperature; D006801:Humans; D007053:Ice; D008297:Male; D010807:Physical Endurance; D013546:Sweating; D013894:Thirst; D055815:Young Adult
chemical_list: D007053:Ice
keywords: gross efficiency; heat storage; pre-cooling; sweating