Headache from sun: what to know

Heat raises the body's need for fluids, while sweating can reduce fluid and salt levels. Bright glare, squinting, and eye strain may add a pressure-like headache. A headache with heavy sweating, weakness, nausea, cramps, or dizziness can occur with heat illness. Fever, cough, sore throat, or body aches suggest an infection may be present instead. The setting and accompanying symptoms matter more than sunlight alone; a sun-related headache does not establish a particular diagnosis.

Stop exertion and rest in shade or an air-conditioned room. Loosen extra clothing, cool the skin with a damp cloth, and sip water or an oral rehydration drink if you are awake and able to drink. Avoid alcohol and further heat exposure until you feel well. Sunglasses and a hat can reduce glare on future outings, and regular fluids and breaks are useful in hot weather. If symptoms do not settle, contact a clinician or pharmacist before taking medicine.

Get urgent help for confusion, fainting, seizure, inability to drink, very hot skin, severe weakness, breathing difficulty, chest pain, a sudden severe headache, or new weakness or trouble speaking. Seek prompt medical advice if vomiting continues, symptoms worsen after cooling, or fever and marked body aches develop. In a hot environment, these warning signs can indicate serious [Heat Exhaustion](/conditions/heat-exhaustion/) or another condition requiring assessment.

How much heat exposure and fluid loss might explain this episode? Do my medicines or health conditions affect heat tolerance? What plan should I use for fluids, outdoor activity, and recurrence?