2.4. Statistical Analyses
dehydration, fluid loss
DEHYDRATION, REGRESSION, FLUID LOSS
Means ± standard deviation (SD) were used to summarize the data. One-way ANOVA was used to compare pre-exercise body mass, amount (kg) of fluid loss, and % dehydration (change in body mass) and confirm each trial replicated the state and conditions of each participant for each experiment.For the primary outcome variable, cumulative % fluid retained for the 3.5 h period, a 1-way ANOVA was used with the Tukey test applied for post hoc analysis. For variables assessed for change over time, a 2-way ANOVA adjusted for repeated measures was used. These variables included the volume of urine collected (fluid loss) at the standardized times and the change in body mass. When main effects and interactions were identified, a 2-way ANOVA was then applied for differences between time points and a 1-way ANOVA with Tukey tests was applied for data within a time point. An alpha level of 0.05 was selected for statistical significance.For the sub-sample measured for sweat sodium loss, correlation and regression were used to determine the relationship between completeness of rehydration (% fluid retained over 3.5 h) and sodium balance (sodium ingested in the beverage minus sodium lost during exercise). For this, a sample size of 18 was obtained by combining data from six participants for the three treatments. While it can be argued that this violates the independence of data points for correlation, slight differences in sweat sodium concentration, variations in sweat rate and absolute sweat loss within a trial, and different dosages of sodium ingested due to beverage content and the volume needed to restore body mass contribute to the same participants being unique from himself for each of the three experiments.