The Effects of Crushed Ice Ingestion Prior to Steady State Exercise in the Heat

作者：Zimmermann, Matthew^*; Landers, Grant; Wallman, Karen E.; Saldaris, Jacinta

来源：International Journal of Sport Nutrition and Exercise Metabolism, 2017, 27(3): 220-227.

DOI：10.1123/ijsnem.2015-0215

• pre-cooling
• sweating
• heat storage
• gross efficiency

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 VO2peak preceded by 30 min of precooling whereby 7 g.kg(-1) of thermoneutral water (CON) or crushed ice (ICE) was ingested. The reduction in Tc at the conclusion of precooling was greater in ICE (-0.9 +/- 0.3 degrees C) compared with CON (-0.2 +/- 0.2 degrees C) (p pound .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.

• 出版日期2017-6