Palatability and Voluntary Intake of Three Commercially Available Sports Drinks and Unflavored Water during Prolonged Exercise in Hot and Humid Conditions

Abstract

PURPOSE: This study compared the palatability and voluntary intake of beverages that have different sensory characteristics, between male and female athletes while running or racewalking in a tropical climate. METHODS: Thirty-six athletes (runners n=31; racewalkers n=5), 18 males (M;mean age=18.9 ± 3.5 yr) and 18 females (F;mean age=20.1± 4.7 yr), were recruited. Subjects completed four 90-minute sessions, running or race walking outdoors (mean distance M=18.0 ± 1.7; F=13.1 ± 2.0 km) at an intensity requiring 80 to 85% of age predicted maximum heart rate in a hot and humid environment (WBGT=30.1±1.1oC) on separate days. One of 4 commercial beverages was offered on each occasion: unflavored water (W), 6% carbohydrate-electrolyte solution (CES), 6% carbohydrate-electrolyte + preservatives solution (CESP1) or 8% carbohydrate-electrolyte + preservatives + B vitamins solution (CESP2). Beverage order was assigned in a Latin Square, double-blind design. They were served cold in squeeze bottles and subjects drank as desired. Palatability was measured during a one-minute exercise break at 15-minute intervals using visual analog 10-point scales and 9-point category scales. RESULTS: There were no differences between conditions (P > 0.05) in environmental variables, exercise intensity or sweat rates. The amounts consumed of the four beverages were similar and insufficient to match sweat rates (W = 17.0 ± 4.8; CES=16.9 ± 5.4; CESP1=17.8 ± 5.4; CESP2=17.5 ± 5.2 ml.kg-1, P>0.05). Males showed a higher fluid intake (18.5 ± 5.4 vs. 16.1 ± 4.7 ml.kg-1, P=0.006) but greater level of dehydration (2.6 ± 0.7 vs. 1.5 ± 0.8 % BM) in all conditions (P < 0.001). No differences were found between males and females in overall acceptance, liking of flavor or thirst quenching at any time point. CONCLUSIONS: Female athletes replaced more of their sweat losses than males but both groups finished dehydrated, with no differences among beverages. Contrary to a previous report in older individuals, females did not drink more water than males. The reluctance of young athletes to drink while running or racewalking in a hot and humid outdoor environment did not seem to be due to the palatability of these beverages and should be further investigated.