Can dehydration be prevented?

Your body loses water through urine, sweat, breathing, vomiting, and diarrhoea. Risk rises when you cannot drink enough to replace those losses, such as during gastroenteritis, fever, exercise, or hot weather. Thirst is useful but may not appear promptly, particularly in older adults and young children. Darker urine, passing urine less often, dry mouth, headache, tiredness, and dizziness can be early clues.

Keep fluids available and take regular drinks throughout the day. Drink more during heat, physical activity, fever, vomiting, or diarrhoea, taking small frequent sips if your stomach feels unsettled. Choose water or other suitable drinks, and ask a pharmacist about an oral rehydration solution when illness causes substantial fluid loss. Wear light clothing in hot conditions, take cooling breaks, and avoid relying on alcohol when you need to replace fluids. If you have heart or kidney disease, follow the fluid plan given by your clinician.

Seek medical advice when vomiting or diarrhoea prevents drinking, symptoms continue despite fluids, or a child, older adult, or person with a long-term illness is becoming drowsy or weak. Get urgent help for fainting, confusion, severe weakness, very little urine, rapid breathing, or inability to keep any fluid down. Heat-related symptoms with worsening dizziness, collapse, or altered behaviour need urgent assessment.

Ask which drinks or rehydration products suit you, how illness should change your fluid plan, and whether a medicine or medical condition makes dehydration more likely. Mention repeated episodes or ongoing diarrhoea rather than treating them only with extra drinks.