Post-exercise ingestion of lactose-free skim milk affects thirst but not subsequent performance and net fluid balance of collegiate badminton athletes

Abstract

Introduction: The hydration and nutritional needs of badminton athletes are of interest because of the unique demands of the sport on the player's physiology and skill. Objective: The current study investigated the acute effect of lactose-free skim milk (LFM) compared with a iso-volumic carbohydrate electrolyte sport drink (iCE) taken post exercise, on subsequent performance, net fluid balance (NFB) and other selected subjective variables (thirst, gastrointestinal comfort and palatability). Methods: Eleven collegiate badminton athletes (five male and six female, mean age=19.6±1.7 years, body mass=56.8±5.0 kg) volunteered to participate in this crossover study, with ≥7-day washout between trials. After a 2 h training session, the participants rested for 2 h, ingested the same volume of either LFM or iCE matched for carbohydrate content of 1.0 g carbohydrate/kg body mass. Performance tests were done post-ingestion. The body mass was taken, as well as visual analog scales administered throughout the protocol. Results: No significant difference between groups was found in terms of performance: aerobic capacity t(10)=0.147, p=0.886 and agility (sideways agility test: t(10)=0.191, p=0.852 and four-corner agility test: t(10)=0.397, p=0.700); and NFB t(10)=0.434, p=0.670. Thirst ratings between groups were significantly different at the end of the performance tests (LFM 6.71±2.09 and iCE 8.03±1.28, t(10)=-2.35, p=0.041). However, the subjective ratings for gastrointestinal comfort and palatability were similar. Conclusion: When matched for carbohydrate content, acute post-exercise ingestion of LFM offered a significant advantage over the sports drink in terms of thirst after subsequent performance.