Ways to prevent dehydration

Dehydration occurs when the body loses more fluid than it replaces. Heat, exercise, fever, vomiting and diarrhoea can increase losses. Thirst, a dry mouth, tiredness, dizziness, constipation or dark urine may be clues, although thirst is not always reliable in older adults. Fluid needs also vary with health conditions, medicines, pregnancy and activity.

Keep water available and drink at regular intervals, especially in hot weather, during exercise and while travelling. Take extra fluids when sweating, and include soups, fruit and vegetables if they suit your diet. During vomiting or diarrhoea, use small frequent sips; an oral rehydration solution may replace water and salts more effectively than plain water alone. Avoid relying on alcohol, which can worsen fluid loss. Do not force large amounts if a clinician has told you to restrict fluids because of heart or kidney disease. Ask how much is right for you, particularly if you take medicines that affect fluid balance.

Seek urgent help for confusion, fainting, severe weakness, very little urine, inability to keep fluids down or signs of shock. Contact a clinician when diarrhoea or vomiting persists, urine remains dark despite drinking, or you have worsening dizziness. A healthcare professional can check for dehydration and conditions such as gastroenteritis, heat exhaustion or a urinary problem.

How much should I drink with my medical conditions? Do any of my medicines alter fluid or salt balance? Which rehydration product should I use during vomiting or diarrhoea?