What should you know about hangover dehydration?

Alcohol can increase urine production, while nausea, vomiting, sweating, heat, and simply forgetting to drink reduce your fluid balance. You may notice darker urine, a dry tongue, tiredness, constipation, or light-headedness when standing. Dark urine alone does not prove that a hangover is the only cause; pain, fever, diarrhoea, or urinary symptoms may point to another problem such as gastroenteritis or a urinary tract infection.

Sip water regularly rather than forcing a large amount at once. An oral rehydration drink may help if you have been vomiting or have diarrhoea; follow its packet directions. Eat small, simple meals when tolerated and rest somewhere cool. Avoid more alcohol, and do not use strenuous exercise to “sweat it out”. If you have kidney, heart, or liver disease, ask a clinician how much fluid is suitable. Persistent dark urine or flank pain deserves assessment, including consideration of kidney stones.

Get urgent help if you cannot keep fluids down, faint, become confused, breathe unusually fast, pass very little urine, or feel severely weak. Seek prompt review for ongoing vomiting, blood in vomit or stool, severe abdominal pain, fever, or symptoms after heat exposure. Heat exhaustion can worsen fluid loss, and severe dehydration may need treatment beyond drinks.

Ask whether your symptoms fit dehydration or suggest another illness, which rehydration drink is appropriate, and whether medicines you take affect fluid balance. Mention vomiting, diarrhoea, urinary changes, pain, and any kidney or heart condition.