Effects of Isotonic and Hypotonic Drinks in Between Repeated Endurance Exercises on Fluid Balance, Blood Glucose, Lactate Levels and Performance in Young Healthy Subjects

Abstract

Suwannachak C, Masodsai K, Chaunchaiyakul R, Kongprasert S, Tongtako W, Cheunsiri N, Suksom D. Effects of Isotonic and Hypotonic Drinks in Between Repeated Endurance Exercises on Fluid Balance, Blood Glucose, Lactate Levels and Performance in Young Healthy Subjects. JEPonline 2022;25(3):82-91. Seventeen healthy active males 18 to 25 years of age participated in two cycling exercises. Following the first high-intensity intermittent cycling (EX1), the 1-hour recovery duration was allowed. The three solutions of placebo (PL), isotonic (ID), and hypotonic drinks (HD) were then randomly assigned in the 1.5 folds of weight reduction from EX1. The progressive load up to exhaustion cycling (EX2) was tested. Hydration status and changes in blood-related metabolites were determined using urine specific gravity and blood osmolality, blood glucose and lactate concentrations. Physical performance was determined from time-to-exhaustion during EX2. HD and ID provided a similar euhydration status without differences in performance. During the subsequent exhaustive exercise, neither HD nor ID exerted any distinction as to fluid balance, blood glucose, lactate, and performance.