What should you know about symptoms of heat stroke and dehydration?

Dehydration means the body has lost more fluid than it has replaced. Heat illness may add heavy sweating, weakness and headache. Heat stroke is a medical emergency involving dangerous overheating and changes such as confusion, unusual behaviour, collapse or seizure. Dark urine can reflect concentrated urine, but cloudy urine, pain or fever may point to another problem such as infection or stones.

For a person who is alert, move them somewhere cool, loosen clothing and offer small sips of water or an oral rehydration drink. Use cool cloths and airflow. Do not force fluids if the person is confused, vomiting repeatedly or unable to swallow. Keep monitoring breathing and responsiveness while arranging help.

Call emergency services for confusion, fainting, seizure, severe weakness, very hot skin, repeated vomiting or inability to drink. Urgent assessment is also needed when urine output remains very low, symptoms do not improve with cooling, or dark or cloudy urine occurs with pain, fever or blood.

Ask how much fluid is suitable for you if you have heart or kidney disease, and whether a recent illness such as gastroenteritis could explain fluid loss. Discuss a plan for hot days and symptoms that should prompt testing.