Heat dehydration symptoms

Sweating cools the body but also removes fluid. If intake does not keep pace, the mouth may feel dry, energy may fall and urine can become concentrated or [Dark Urine](/symptoms/dark-urine/) may appear. Constipation can also occur when the body has less available fluid.

Heat-related dehydration may occur with heat exhaustion, diarrhoea or vomiting. [Gastroenteritis](/conditions/gastroenteritis/) can cause fluid loss, while pain or urinary changes may have other explanations such as [Kidney Stones](/conditions/kidney-stones/) or a [Urinary Tract Infection](/conditions/urinary-tract-infection/).

Stop exertion, move somewhere cool and loosen clothing. Sip water regularly and rest. If vomiting or diarrhoea is present, ask a pharmacist or clinician about a suitable rehydration drink. Avoid alcohol and further heat exposure while symptoms continue.

Monitor alertness, ability to drink and urination. [Cloudy Urine](/symptoms/cloudy-urine/) or persistent urinary symptoms should not automatically be attributed to dehydration.

Seek urgent help for confusion, fainting, seizure, inability to drink, repeated vomiting, severe weakness, very little urine, breathing difficulty or worsening symptoms after cooling. These can signal severe dehydration or a dangerous heat illness.

Ask what may be causing the fluid loss, which drinks suit your medical conditions, and whether medicines need review. Mention sweating, vomiting, diarrhoea, urine changes and how symptoms respond to cooling.