02), although this was still within

the normal reference range. Sweat indices Sweat rate (placebo, 0.71 ± 0.29 L.h-1; sodium, 0.55 ±0.22 L.h-1; P = 0.19) and sweat sodium concentration (placebo, 34.0 ± 14.2 mmol.L-1; sodium, 37.3 ± 16.2 mmol.L-1; P = 0.70) were not different between the interventions (Table 3). Consequently, there was check details no significant difference observed in sweat sodium loss (placebo, 25.3 ± 16.8 mmol.h-1; sodium, 26.3 ± 16.2 mmol.h-1; P = 0.29), although the Cohen’s d effect size of this comparison is 0.59, indicating a medium effect of the sodium group having higher sweat [Na+] losses. Sweat chloride concentration was not different between interventions (P = 0.68). Table 3 Sweat losses and electrolyte concentrations   Placebo Sodium P Sweat rate (L.hr-1) 0.71 ± 0.29 0.57 ± 0.22 0.25 Sweat [Na+] (mmol.L-1) 34.0 ±14.2 37.3 ± 16.2 0.70 Sweat sodium

loss (mmol.h-1) 25.3 ± 16.8 26.3 ± 16.2 0.29 Sweat [Cl-] (mmol.L-1) 43.5 ± 18.2 39.5 ± 21.9 0.68 Mean ± SD sweat rate (L.h-1), sweat sodium concentration (mmol.L-1), sweat sodium loss (mmol.h-1), and sweat chloride concentration (mmol.L-1) among participants when consuming sodium supplements and placebo. Fluid balance Athletes began the time-trial equally hydrated in both trials, according to their pre-race urine osmolality (P = 0.91) (Table 4). This hydration status did not change across the time-trial, and the relative change in urine osmolality from pre-race to post-race was not different between interventions (P = 0.43). No participant urinated during either of the time trials. Participants in both the placebo and sodium intervention lost a mean of 1% body mass over the Inflammation related inhibitor course Dasatinib of the time trial, from pre-race to post-race. This relative change in body mass was Carbohydrate not different between the two interventions (P = 0.52). Table 4 Measures of fluid balance   Placebo Sodium P Relative body mass change (%) −1.04 ± 0.55 −0.99 ± 0.80 0.52 Relative plasma volume change (%) −0.85 ± 1.83 1.78 ± 2.23 0.02* Pre-race urine osmolality (mosmol.L-1) 509.9 ± 295.2 493.7 ± 263.7 0.91 Relative urine osmolality change (%) 31.5 ± 121.7 −6.1 ± 43.6 0.43 Fluid intake rate

(mL.h-1) 268.9 ± 65.0 428.42 ± 166.3 0.01* Thirst changea −0.6 ± 34.2 20.0 ± 23.0 0.17 apost-pre, difference in subjective score out of 100; * P < 0.05. Mean ± SD fluid balance variables: absolute (kg) and relative (%) body mass change, absolute (mL) and relative (mL.h-1) fluid intake, relative (%) hamatocrit change and pre-trial urine osmolality (mOsmol.kg-1) among athletes consuming sodium supplements and placebo. Whilst the absolute haematocrit values at pre-race were similar between the interventions, the changes in these values across the time-trial were different. Haematocrit significantly reduced during the sodium intervention by 3% (P = 0.02), which was significantly different from the observed change in the placebo group, which increased by 1.5% (P = 0.02).