CRAMPS are mostly unpleasant painful sensations caused by muscle contraction or over-shortening. Common causes of skeletal muscle cramps may include muscle fatigue, low sodium, low potassium, and/or low magnesium. Smooth muscle cramps may be due to menstruation or gastroenteritis. Causes of cramping include hyperflexion, hypoxia, exposure to large changes in temperature, dehydration, or low blood salt and electrolytes.