Case Study: Symptomatic Exercise-Associated Hyponatremia in an Endurance Runner Despite Sodium Supplementation.

Symptomatic exercise-associated hyponatremia (EAH) is known to be a potential complication from overhydration during exercise, but there remains a general belief that sodium supplementation will prevent EAH. We present a case in which a runner with a prior history of EAH consulted a sports nutritionist who advised him to consume considerable supplemental sodium, which did not prevent him from developing symptomatic EAH during a subsequent long run. Emergency medical services were requested for this runner shortly after he finished a 17-hr, 72-km run and hike in Grand Canyon National Park during which he reported having consumed 9.

Hiker Fatality From Severe Hyponatremia in Grand Canyon National Park.

We present the case of a hiker who died of severe hyponatremia at Grand Canyon National Park. The woman collapsed on the rim shortly after finishing a 5-hour hike into the Canyon during which she was reported to have consumed large quantities of water. First responders transported her to the nearest hospital.

Three cases of severe hyponatremia during a river run in Grand Canyon National Park.

We present 3 cases of severe hyponatremia occurring on a commercially guided river rafting trip on the Colorado River in Grand Canyon National Park. All 3 women appeared to have been overhydrating because of concern about dehydration and required evacuation within 24 hours of each other after the staggered onset of symptoms, which included fatigue and emesis progressing to disorientation or seizure. Each was initially transferred to the nearest hospital and ultimately required intensive care.