Does a Reduction in Serum Sodium Concentration or Serum Potassium Concentration Increase the Prevalence of Exercise-Associated Muscle Cramps?
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Updated: Apr 13, 2026

Induction and Assessment of Exertional Skeletal Muscle Damage in Humans
Published on: December 11, 2016
Donal Murray1, Kevin C Miller, Jeffrey E Edwards
1Dept of Rehabilitation Science, George Mason University, Fairfax, VA.
Clinical Scenario:
Although exercise-associated muscle cramps (EAMC) are common in ultradistance runners and athletes in general, their etiology remains unclear. EAMC are painful, sudden, involuntary contractions of skeletal muscle occurring during or after exercise and are recognized by visible bulging or knotting of the whole, or part of, a muscle. Many clinicians believe EAMC occur after an imbalance in electrolyte concentrations, specifically serum sodium concentration ([Na+]s) and serum potassium concentration ([K+]s). Studies that have established a link between EAMC occurrence and serum electrolyte concentrations after an athletic event are unhelpful. Focused Clinical Question: Are [Na+]s and [K+]s different in athletes who experience EAMC than noncrampers?
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