Muscle cramps are involuntary contractions of muscles that can last from a few seconds to several minutes and are often painful. They can occur suddenly and may be visible; specific types include exercise-associated muscle cramps and nocturnal leg cramps.

The main symptom of a muscle cramp is a sudden, involuntary, and painful contraction of a muscle, which can leave lingering pain even after the cramp subsides. Muscle cramps may also feel like hardness in the affected muscle and are often attributed to muscle fatigue and nerve dysfunction rather than dehydration or electrolyte imbalances.

Muscle cramps are diagnosed clinically by identifying common symptoms such as sudden painful muscle contractions, which may feel hard to the touch. Various triggers, including vigorous exercise and certain muscle positions, can also indicate the presence of muscle cramps.

Drugs are not recommended as the first line treatment for routine muscle cramps. Instead, relief can often be achieved through stretching, massage, and allowing the muscle to rest after an initial contraction.

There is limited evidence regarding the effectiveness of supplements for muscle cramps; magnesium has shown ineffectiveness in older adults and mixed results in pregnancy. Some small studies suggest that certain B-complex supplements may help reduce muscle cramps, particularly in older adults with hypertension and pregnant individuals, whereas calcium and vitamin D have not consistently proven effective.

Although dehydration and electrolyte imbalances are often considered to be causes of muscle cramps, evidence suggests that cramps are more likely related to abnormal muscular control rather than hydration status. However, maintaining a balanced diet with adequate hydration and electrolytes can help alleviate cramps for some people.

Quinine derivatives can help with muscle cramps but are no longer recommended due to toxicity risks; other treatments like nafronyl, calcium channel blockers, and IVs of magnesium or calcium may have some effects but come with potential complications. Hydration and electrolyte drinks are commonly used, though their effectiveness in treating cramps is debated.

The exact cause of muscle cramps is not well understood, but dehydration, electrolyte imbalances, muscle fatigue, and nerve dysfunction are potential factors. Additionally, rare causes such as certain medications and specific diseases may also contribute to muscle cramps and warrant examination by a healthcare professional.