When to worry about muscle cramps with dehydration

Fluid loss from heat, sweating, vomiting, diarrhoea, fever, or not drinking enough can disturb the balance needed for normal muscle contraction. Cramps often affect the legs or other heavily used muscles. They may improve as the cause of fluid loss is corrected, but cramps can have other explanations, including medicines, exertion, or mineral disturbances.

Move to a cooler place, rest, and take frequent small sips of fluid if you are awake and able to swallow. Replace the source of loss where possible and avoid strenuous activity until you feel better. Ask a pharmacist or clinician whether an oral rehydration product is appropriate, particularly after vomiting or diarrhoea or if you have kidney or heart disease.

Get prompt medical help if you cannot keep fluids down, are passing very little urine, feel persistently dizzy, or remain unusually weak despite resting and drinking. Emergency care is needed for fainting, confusion, severe drowsiness, seizures, trouble breathing, or inability to swallow. Heat exposure with worsening symptoms also needs urgent attention.

Ask what fluid is suitable for your situation, whether medicines or illness increased your fluid loss, and how to recognise dehydration early next time.