Sodium Supplementation and Exercise-Associated Hyponatremia (EAH) during Prolonged Exercise (ultramarathon running)

Weight loss of around 4% body weight (relative to pre race weight) can be anticipated to maintain euhydration in such a prolonged event

Those who become symptomatic with EAH have either gained weight or lost less that 3-4% body weight

Overhydration rather than inadequate supplemental sodium intake is a greater contributor to the development of EAH

There is a suggested link between EAH and rhabdomyolysis. The mechanism remains unknown and it is unclear which condition may augment the other. Further research is needed.

Take home: Avoid overhydration during prolonged exercise to prevent EAH.

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