Nocturnal leg cramps are sudden contractions of the lower leg and foot muscles. They often awaken you from sleep. The calf muscles are most often involved.

The Calf Muscles
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The specific cause of nocturnal leg cramps is unknown. These cramps may be related to imbalances in local muscle chemistry. Many activities and diseases are associated with nocturnal leg cramps including:

  • Overexertion of the muscles
  • Prolonged standing on hard surfaces
  • Prolonged sitting
  • Dehydration
  • Diseases:
  • Certain medications:
    • Blood pressure medications
    • Statins taken to lower cholesterol
    • Morphine
    • Lithium