Sodium supplementation alone does not reliably prevent or correct hyponatremia risk during Ironman-distance racing
Interpretation
Hew-Butler et al.'s randomized trial across 413 Ironman finishers found no significant differences in serum sodium, finishing time, or weight change between sodium-supplemented, placebo, and no-supplementation groups — sodium tablets alone did not measurably affect hyponatremia-relevant outcomes in this trial.
Practical implication
Don't position salt tablets as a primary hyponatremia-prevention strategy. Fluid-intake moderation (not drinking to excess relative to sweat losses) is the better-supported lever to emphasize.
Sources
1 source, independently verified.
BJSM 40(3):255-259. Randomised sodium (620mg), placebo (596mg starch), or no supplementation; no significant between-group differences in serum sodium, finishing time, or body-weight change — sodium tablets alone did not prevent or meaningfully affect hyponatremia risk in this trial.