Further the results of this study showed large variability in the change in plasma volume from pre- to post- exercise, so the effects of sodium supplementation

maybe more Necrostatin-1 order pronounced in some individuals, potentially due to differences VX-680 mouse in training status or regular dietary sodium intakes. Indeed six of the participants did perform better on the sodium trail, although there was no statistical significant difference in performance in this study. Therefore the results may suggest that some individuals respond to sodium ingestion during exercise whilst others do not, this may be due to differences in training status, sweat sodium losses or renal handling of sodium. Plasma sodium concentration Plasma sodium was significantly greater among the sodium group compared to the placebo group before the time-trial started. Sodium intakes demonstrate considerable day-to-day variation both between and within individuals [24], making dietary manipulation extremely difficult. Such a chronic dietary manipulation would have significantly increased participant burden and may have affected sodium balance during the time-trial. Indeed, whilst the

pre-race plasma [Na+] values were statistically different between the groups, this difference was small (1.6 mmol.L-1), and both groups were within the normal reference range. Pre-race plasma [Na+] had little effect on the change of plasma [Na+] during the time-trial, which remained the same in both groups. In line with the PRI-724 cell line findings of Barr PJ34 HCl et al. [7], similar plasma [Na+] levels were seen between the trials immediately following exercise (post-race), regardless of whether the participants received a sodium supplement

or not, suggest that during an exercise session of this duration, sodium supplementation has little effect on plasma sodium concentrations. However, as all participants remained in the normal reference range of plasma [Na+], with no athletes developing hyponatremia, the lowest plasma [Na+] value being 137 mmol.L-1, which occurred during the placebo trial. Whether sodium supplementation would be beneficial in situations where the risk of EAH is greater can not be resolved by this study. Much like previous field studies which found no change in plasma [Na+] during an Ironman Triathlon [10, 11], the athletes in this study were free to consume fluids ad libitum. This protocol differs from laboratory studies that often had athletes consuming fluid equal to sweat rate [4–6], which some have suggested is over-drinking and possibly not reflective of the majority of athletes’ intake during exercise [10].