How to avoid dehydration

Keep drinks accessible and respond to thirst before long periods outdoors, exercise or travel. Vomiting and diarrhoea may require small, frequent sips of an oral rehydration solution rather than large drinks taken quickly.

Water leaves the body through urine, sweat, breathing and stool. Hot or humid conditions, fever, strenuous activity, vomiting and diarrhoea can accelerate those losses. Young children, older adults and people who depend on others for drinks may not replace fluid promptly.

Thirst, a dry mouth, tiredness, dizziness and passing less urine can appear as fluid balance falls. Dark urine can support the picture, although medicines, foods and some medical conditions can also change urine colour.

Drink at intervals across the day and take extra fluid before and during prolonged heat exposure. Wear light clothing, schedule outdoor activity for cooler periods and take shaded or air-conditioned breaks. Water suits routine needs, while substantial losses from gastroenteritis may also require salts and glucose in a correctly mixed rehydration solution.

Offer frequent small amounts to someone who feels sick. Continue breastfeeds for a breastfed baby and seek clinical advice early for an infant or anyone unable to maintain intake. People with heart or kidney conditions should follow their prescribed fluid plan rather than increasing drinks without guidance.

Seek urgent care for confusion, fainting, severe weakness, very little or no urine, rapid breathing, inability to keep fluids down, blood in vomit or stool, or worsening drowsiness. A child who is unusually sleepy, has no tears when crying or feeds poorly also needs prompt assessment.

Move a person with suspected heat exhaustion into a cool place, loosen excess clothing and begin cooling while arranging help. Collapse, seizures or altered awareness in the heat require emergency services.

Ask how illness, pregnancy, age, kidney function or medicines affect your fluid needs. If vomiting or diarrhoea is present, clarify which rehydration product to use, how to mix it, and what change in urine output or alertness should trigger immediate care.