Most people have experienced muscle cramps, usually in the form of leg cramps. Surveys suggest that one‐third of adults over 60 years old and half of those over 80 experience muscle cramps, some reporting symptoms for ten years or longer. They strike without warning, often in the night, and usually, slowly respond as one keeps the extremity involved on stretch until the cramps subside. Extrapolating from the experiences of athletes who get exercise‐induced cramps and people with peripheral vascular disease who get activity‐related cramps, one would assume that muscle cramps must represent muscle fatigue, electrolyte imbalance, or tissue ischemia. Yet, many muscle cramps occur temporally distant from any physical exertion and often when hydration is not an issue. And for many athletes, hydration or electrolyte solutions have failed to prevent or adequately treat their occurrence.