title: Fatal water intoxication and cardiac arrest in runners during marathons: prevention and treatment based on validated clinical paradigms.
abstract: Cerebral edema due to exercise-associated hyponatremia and cardiac arrest due to atherosclerotic heart disease cause rare marathon-related fatalities in young female and middle-aged male runners, respectively. Studies in asymptomatic middle-aged male physician-runners during races identified inflammation due to skeletal muscle injury after glycogen depletion as the shared underlying cause. Nonosmotic secretion of arginine vasopressin as a neuroendocrine stress response to rhabdomyolysis mediates hyponatremia as a variant of the syndrome of inappropriate antidiuretic hormone secretion. Fatal hyponatremic encephalopathy in young female runners was curtailed using emergent infusion of intravenous hypertonic (3%) saline to reverse cerebral edema on the basis of this paradigm. This treatment was arrived at through a consensus process within the medical community. An increasing frequency of cardiac arrest and sudden death has been identified in middle-aged male runners in 2 studies since the year 2000. Same-aged asymptomatic male physician-runners showed post-race elevations in interleukin-6 and C-reactive protein, biomarkers that predict acute cardiac events in healthy persons. Hypercoagulability with in vivo platelet activation and release of cardiac troponin and N-terminal pro-brain natriuretic peptide were also observed post-race in these same subjects. High short-term risk for atherothrombosis during races as shown by stratification of biomarkers in asymptomatic men may render nonobstructive coronary atherosclerotic plaques vulnerable to rupture. Pre-race aspirin use in this high-risk subgroup is prudent according to conclusive evidence for preventing first acute myocardial infarctions in same-aged healthy male physicians. On the basis of validated clinical paradigms, taking a low-dose aspirin before a marathon and drinking to thirst during the race may avert preventable deaths in susceptible runners.
authors.affiliation: McLean Hospital, Belmont, Mass; Harvard Medical School, Boston, Mass. Electronic address: asiegel@partners.org.
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Siegel
mesh_terms: D016757:Death, Sudden, Cardiac / Q000209:etiology / Q000517:prevention & control; D006323:Heart Arrest / Q000209:etiology / Q000401:mortality / Q000517:prevention & control / Q000628:therapy*; D006801:Humans; D012420:Running; D014869:Water Intoxication / Q000209:etiology / Q000401:mortality / Q000517:prevention & control / Q000628:therapy*
keywords: Aspirin; Cardiac arrest; Cardioprotection; Exercise-associated hyponatremia; Hypertonic (3%) saline; Marathon