Why does heat exhaustion cause headache?

As the body works hard to cool itself, sweating can reduce fluid and salt stores. Heat can also widen blood vessels and make the heart work harder to send blood to the skin for cooling. Together, these changes may leave you with a throbbing or pressure-like head pain, tiredness, dizziness, thirst, heavy sweating or muscle cramps. Headache is a common presentation of Heat Exhaustion, but a headache has many possible causes.

Stop activity and move into air conditioning, shade or another cool place. Loosen extra clothing, cool the skin with damp cloths or a fan, and rest lying down or seated. If you are awake and can swallow, take small, frequent sips of a cool drink. Avoid alcohol and strenuous exercise until you feel recovered. Do not leave a person who is becoming more unwell alone.

Get emergency help if there is fainting, confusion, a seizure, trouble speaking, chest pain, severe breathlessness, collapse, or hot skin with a marked change in alertness. Seek medical advice promptly if vomiting prevents drinking, the headache is severe or unusual, symptoms do not settle after cooling and rest, or they return with activity. These signs need assessment because heat illness can worsen quickly.

Ask whether your medicines, heart conditions, kidney conditions or previous heat illness could affect fluid balance or heat tolerance. You can also ask for a personalised plan for outdoor work, exercise and recognising early warning symptoms.