Exercise associated hyponatraemia (EAH)

• definition of exercise-associated hyponatraemia (EAH):
  • hyponatremia (less than the laboratory reference range usually < 135mmol Na+) occurring during or up to 24 hours of prolonged exertion (usually > 4 hrs duration) (1)

EAH should be classified using the same clinical criteria as any acute or rapid onset hyponatremia

• most important factor is determining the presence or absence of clinical signs and symptoms: specifically neurological manifestations
• in general, the lower the [Na+] the more severe the neurological signs and symptoms
  • however, individual variability is great and the numerical value of [Na+] is not a reliable predictive index of the clinical severity of hyponatremia, including EAH

Contributors (September 2010):

• Dr Volker Scheer (GP Locum), Dr Andrew Murray (Marathon Medical Services)

Reference:

• 1) Hew-Butler T, Ayus JC, Kipps C, Maughan RJ, Mettler S, Meeuwisse WH, Page AJ, Reid SA, Rehrer NJ, Roberts WO, Rogers IR, Rosner MH, Siegel AJ, Speedy DB, Stuempfle KJ, Verbalis JG, Weschler LB, Wharam P.Statement of the Second International Exercise-Associated Hyponatremia Consensus Development Conference, New Zealand, 2007. Clin J Sport Med. 2008 Mar;18(2):111-21
• 2) www.overhydration.org