What to know about dehydration in older adults

Dehydration happens when the body loses more fluid than it takes in. Older adults can be more vulnerable because thirst may become less noticeable, mobility problems may make drinks harder to reach, and illness, fever, vomiting, diarrhoea, or medicines that increase urination can change fluid needs. Signs may include a dry mouth, darker urine, passing urine less often, constipation, headache, dizziness, unusual tiredness, or new confusion. These signs can have other causes, so a change from usual function deserves attention.

Offer small, frequent drinks through the day unless a clinician has advised fluid restriction for a heart or kidney condition. Keep a drink within easy reach and include fluid-rich foods such as soup, yoghurt, or fruit when suitable. During illness, seek advice about replacing fluid and salts rather than relying on one type of drink. Record changes in drinking and urination if monitoring is difficult, and review medicines with a clinician instead of stopping them independently.

Get urgent medical help for severe confusion, fainting, inability to keep fluids down, very little or no urine, marked weakness, rapid breathing, or difficulty staying awake. Contact a clinician promptly when dizziness, reduced urination, diarrhoea, vomiting, or a sudden behaviour change continues. An older person who lives alone may need someone to check in and help arrange assessment.

Ask which daily fluid pattern is suitable, whether any heart or kidney condition changes that advice, and whether current medicines can worsen fluid loss. Ask how to distinguish dehydration from infection, low blood pressure, or a medicine side effect, and what warning signs should prompt same-day care.