Ice slurry ingestion does not enhance self-paced intermittent exercise in the heat

Abstract

This study aimed to determine if ice slurry ingestion improved self-paced intermittent exercise in the heat. After a familiarisation session, 12 moderately trained males (30.4 ± 3.4 year, 1.8 ± 0.1 cm, 73.5 ± 14.3 kg,O2max 58.5 ± 8.1 mL/kg/min) completed two separate 31 min self-paced intermittent protocols on a non-motorised treadmill in 30.9 ± 0.9 °C, 41.1 ± 4.0% RH. Thirty minutes prior to exercise, participants consumed either 7.5 g/kg ice slurry (0.1 ± 0.1 °C) (ICE) or 7.5 g/kg water (23.4 ± 0.9 °C) (CONTROL). Despite reductions in Tc (ΔTc: −0.51 ± 0.3 °C, P < 0.05) and thermal sensation prior to exercise, ICE did not enhance self-paced intermittent exercise compared to CONTROL. The average speed during the walk (CONTROL: 5.90 ± 1.0 km, ICE: 5.90 ± 1.0 km), jog (CONTROL: 8.89 ± 1.7 km, ICE: 9.11 ± 1.5 km), run (CONTROL: 12.15 ± 1.7 km, ICE: 12.54 ± 1.5 km) and sprint (CONTROL: 17.32 ± 1.3 km, ICE: 17.18 ± 1.4 km) was similar between conditions (P > 0.05). Mean Tsk, Tb, blood lactate, heart rate and RPE were similar between conditions (P > 0.05). The findings suggest that lowering Tc prior to self-paced intermittent exercise does not translate into an improved performance.