Author(s): YAMAGUCHI, H., HIROE, Y., YAMAMOTO, Y., MORI, T., HANANO, H., OISHI, K., IKEUE, K., ISHII, K., Institution: DOSHISHA UNIVERSITY, Country: JAPAN, Abstract-ID: 1262

INTRODUCTION:
Ice slurry ingestion has attracted attention as an effective way to suppress the exercise-associated rise in core body temperature [1]. Heat countermeasures, including heat stroke, control excessive increase in body temperature and ensure efficient absorption of ingested fluids by the body. Gastric emptying rate (GER) is indicative of fluid absorption, and delayed GER results in delayed absorption of water and nutrients, leading to decreased performance. After exercise, taking measures to avoid delaying GER is crucial to replenish lost fluids and electrolytes. Previous studies have reported transient and minor effect of the ingested beverage temperature (4–50℃) on GER [2,3]; however, thus far, the effect of ingesting ice slurry (−1°C) on GER remains unclear. Understanding the effect of ice slurry ingestion on GER could inform recommendations for optimal fluid intake methods during exercise. This study aimed to determine the effect of ice slurry ingestion after exercise on gastric emptying.
METHODS:
Nine healthy male students (22.3 ± 2.0 years, 169.3 ± 2.7 cm, 64.9 ± 11.2 kg) were recruited. They performed cycling exercises in the laboratory for 20 min at 60% VO2max and then ingested either 200 g of ice slurry (−1°C) or fluid (4°C) prepared with sports drinks on separate days. GER (evaluated by 13C excretion after 13C labeled sodium acetate ingestion), thermal sensation (TS), thermal comfort (TC), and gastric discomfort (GD) were evaluated after consuming each beverage.
RESULTS:
No significant interaction (condition × time) was observed for changes in 13C excretion (interaction: p=0.100, condition: p=0.290, time: p<0.001). The time to maximal 13C excretion rate (Tmax) (an indication of GER) did not significantly differ between ice slurry (33.3 ± 11.9 min) and fluid (32.8 ± 7.5 min) ingestion (p=0.834). No systematic error in Tmax was found between ice slurry and fluid ingestion (95% confidence interval [CI]: −14.503–15.614, B=0.507, p=0.081). Additionally, the TS, TC, and GD did not differ significantly (TS, interaction: p=0.368, condition: p=1.000, time: p<0.001; TC, interaction: p=0.395, condition: p=0.672, time: p<0.001; GD, interaction: p=0.100, condition: p=0.218, time: p=0.100).
CONCLUSION:
These findings suggest that ice slurry ingestion (200 g) after 20 min of cycling exercise does not cause a delay in gastric emptying compared to that with fluid ingestion.

REFERENCE:
1. Siegel, R, and PB. Laursen. Keeping your cool: possible mechanisms for enhanced exercise performance in the heat with internal cooling methods. Sports Med, 2012. 42: 89-98.
2. Shi, X, et al. Gastric emptying of cold beverages in humans: effect of transportable carbohydrates. Int J Sport Nutr Exerc Metab, 2000. 10(4): 394-403.
3. Sun, W.M, et al. Effect of meal temperature on gastric emptying of liquids in man. Gut, 1988. 29(3): 302-305.