How common is excessive thirst in dehydration?

Dehydration happens when the body loses more fluid than it takes in. Along with thirst, you may notice a dry mouth, darker urine, passing urine less often, headache, tiredness, or dizziness. Hot weather, exercise, fever, diarrhoea, vomiting, and not drinking enough can all contribute.

Thirst is useful as a warning sign, but it does not identify the reason for fluid loss. Ongoing thirst may need assessment, particularly if you also have persistent vomiting, diarrhoea, or a medical condition that affects fluid balance.

Move to a cool place, rest, and take regular small sips of fluid if you can drink safely. If diarrhoea or vomiting is involved, a pharmacist can advise on an oral rehydration product. Avoid alcohol while recovering, and pause strenuous activity until you feel well. People with a prescribed fluid restriction should follow their individual medical advice.

Get medical help promptly if you cannot keep fluids down, are becoming confused, faint, very drowsy, or markedly weak. Urgent assessment is also appropriate for very little urine, severe abdominal pain, blood in vomit or stool, or dehydration in a baby, older adult, or someone with a serious long-term condition.

Ask what may be causing the fluid loss, whether oral rehydration is suitable, and when you can return to normal activity. Mention recent travel, heat exposure, medicines, fever, and changes in urine or bowel movements.