Why do we get cramps in our legs?

A cramp is an involuntary, forceful contraction of one or more muscles. Calf cramps are common at night and during exercise. Dehydration and loss of electrolytes like sodium, potassium and magnesium through sweat can trigger them, as these minerals help control muscle contraction. Sitting or lying in an awkward position, overexertion and poor blood flow also play a role. Night cramps become more common with age. Stretching the muscle, massaging it and staying hydrated usually help. If cramps are frequent and severe, a doctor may check for underlying conditions such as nerve compression or circulatory problems.