Effects of sports drink ice slurry ingestion during recovery on cycling performance & thermoregulatory responses in warm-humid environment among trained junior cyclists

This study investigated the effect of sports drink ice slurry ingestion during recovery on cycling performance and thermoregulatory responses in a warm and humid environment. A randomized crossover study design with two separated visits of trials, 7 male Kelantan state cyclist ingested 1.25 g/kg body weight of sport drink ice slurry (0.4°C) and plain water (27°C) during 30-min recovery period after fixed-intensity cycling and time trial exercise bouts (Exercise 1) but before exercising the next subsequent exercise bouts (Exercise 2) in the warm and humid laboratory setting (30.86 ± 0.14°C, 69.32 ± 0.72% RH and 31.01 ± 0.21°C, 67.83 ± 1.29% RH). The average of work performed, rectal and skin temperature, heart rate (HR), rating of perceived exertion (RPE), thermal sensation, and thermal discomfort ratings were measured. The average work completed in the 15-minute time trial for ice slurry (146.9 ± 22.2 kJ) was higher than the control (134.7 ± 28.6 kJ), but it was not significantly different. The heart rate response in Exercise 2 ice slurry was elevated, but there was no significant difference between the two trials, p = 0.572. There was no significant mean difference in core temperature during both exercise bouts between trials, p = 0.512. However, there was a reduction in core temperature with ice slurry in Exercise 2. During exercise, there was a significant difference in mean skin temperature between ice slurry and control trials, p = 0.02. Ice slurry ingestion during recovery did not significantly change RPE (p = 0.543), thermal discomfort (p = 0.972), and thermal sensation (p = 0.732). Ingestion of sports drinks ice slurry improved cycling performance in subsequent exercise compared to plain water ingestion. In addition, ice slurry also attenuated the skin temperatures during the subsequent exercise in a warm and humid environment. However, ice slurry ingestion during recovery did not affect core temperature, heart rate, RPE, thermal discomfort, and thermal sensation in subsequent exercise.