Headache due to heat: what to know

Sweating reduces body fluid and can affect the balance of salts. Heat, exertion, crowded spaces and poor ventilation may add strain. Headache may occur with thirst, dizziness, weakness, cramps, nausea, heavy sweating or dark urine. Those features can indicate heat exhaustion rather than an isolated headache. Fever, infection, migraine and other causes remain possible, particularly if symptoms began indoors or continue after cooling.

Timing matters: note the heat exposure, activity, fluids, urine changes and whether symptoms ease after rest. Children, older adults, pregnant people and those with chronic illness may need help sooner.

Stop exertion and go indoors or into shade. Loosen extra clothing, use cool wet cloths or a fan, and take frequent small sips of water. If you have been sweating heavily, ask a pharmacist about a suitable oral rehydration drink. Avoid alcohol and further strenuous activity until you feel recovered. Do not force fluids in someone who is confused, vomiting repeatedly or unable to swallow.

Get emergency help for confusion, collapse, seizure, loss of consciousness, very hot skin, severe breathing trouble or inability to drink. Seek prompt assessment if vomiting continues, dizziness prevents standing, symptoms worsen or the headache does not improve after cooling and fluids. A sudden severe headache, weakness, speech trouble or stiff neck with fever also needs urgent care regardless of the weather.

Ask how to plan fluids during outdoor work, whether your medicines raise heat sensitivity, and which symptoms mean you should stop activity and seek help.