Does dehydration cause muscle cramps?

A cramp is a sudden, involuntary tightening of a muscle. Dehydration can occur after heavy sweating, exercise, fever, vomiting, or diarrhoea, and the associated fluid and salt loss may make cramping more likely. Cramps often affect the calves, feet, thighs, or hands, but other causes include muscle overuse, prolonged positioning, pregnancy, and some medicines. A cramp therefore does not identify dehydration by itself. Look for accompanying thirst, dry mouth, dizziness, tiredness, darker urine, or reduced urination.

Stop the activity, gently stretch the affected muscle, and use a light massage until it relaxes. Rest in a cool place and take small, regular sips of water. After substantial sweating or gastrointestinal fluid loss, an oral rehydration solution may be appropriate when prepared and used as directed. Ease back into exercise and take breaks in hot conditions. Do not start salt tablets or electrolyte supplements without professional advice, especially if you have kidney, heart, or blood-pressure problems.

Seek urgent care if cramps occur with confusion, fainting, severe weakness, inability to drink, very little urine, chest pain, or breathing difficulty. Arrange a clinical review if cramps are frequent, severe, widespread, last unusually long, disturb sleep repeatedly, or continue after fluids and rest. Medical assessment can check hydration, medicines, circulation, and other muscle or nerve causes.

Could fluid or salt loss be contributing to my cramps? Should I change exercise, heat exposure, or fluid intake? Could any medicine or health condition be involved?