Effects of chronic dehydration

When fluid losses repeatedly exceed intake, urine may become darker or less frequent and the mouth may feel dry. Some people develop headaches, tiredness, dizziness, difficulty concentrating or constipation. Concentrated urine can encourage mineral crystals, which may contribute to kidney stones. Dehydration can also worsen heat exhaustion, especially during hot weather or exercise. Cloudy urine, dark urine and constipation have many possible causes, so they do not by themselves confirm dehydration. Illnesses such as gastroenteritis can increase fluid loss, while urinary symptoms may need assessment for a urinary tract infection.

Drink regularly through the day and increase intake when you sweat, have a fever or lose fluid through vomiting or diarrhoea. Water is suitable for routine thirst, while an oral rehydration solution may be useful when fluid and salts have been lost. Take small sips if nausea makes drinking difficult. Do not force large amounts quickly, and ask a clinician for tailored advice if you have kidney, heart or liver disease or have been told to restrict fluids. Review medicines and working conditions with a healthcare professional if dehydration keeps returning.

Arrange medical advice for ongoing dark urine, repeated dizziness, constipation that does not settle, cloudy urine with urinary discomfort, or thirst that persists despite drinking. Seek urgent help for confusion, fainting, inability to keep fluids down, very little urine, severe weakness or signs of heat illness. These symptoms can reflect a more serious problem than simple low intake.

Ask how much fluid is appropriate for you, whether a medicine or illness is driving the fluid loss, and whether urine or blood tests are needed. Mention your daily drinks, sweating, bowel changes and any urinary pain.