Heat safety

Heat exhaustion vs heatstroke

Short answer

Heat exhaustion needs prompt cooling and fluids. Heatstroke is a medical emergency. Call 999 for signs such as confusion, loss of coordination, seizure, loss of consciousness, very high temperature, or hot skin that is not sweating.

Signs of heat exhaustion

  • ✓Tiredness, dizziness or headache
  • ✓Nausea or vomiting
  • ✓Heavy sweating with pale or clammy skin
  • ✓Cramps, thirst, irritability or a high temperature

What to do

  • ✓Move the person to a cool place and stay with them.
  • ✓Remove unnecessary clothing.
  • ✓Give cool water if they can drink.
  • ✓Cool their skin with cool water and airflow. Use cold packs wrapped in cloth under the armpits or on the neck.

When it is an emergency

Call 999 for possible heatstroke

Call 999 if the person is still unwell after 30 minutes of cooling and fluids, or has a very high temperature, hot skin without sweating, fast breathing, confusion, poor coordination, a seizure or loss of consciousness. Follow the call handler’s instructions.

About this guidance

This page cannot diagnose anyone. If you are struggling to treat heat-exhaustion symptoms or need advice, contact NHS 111.

Related guides

How to cool a room without air conditioning →How to sleep during a heatwave →How fans cool you →

Sources & evidence

Reviewed 2026-08-21

  1. NHS: Heat exhaustion and heatstroke ↗

    Supports: Symptoms, first response, NHS 111 advice and emergency action.

    health guidance · Accessed 2026-08-21

  2. UK Health Security Agency: Beat the heat: keep cool at home checklist ↗

    Supports: Window timing, shading, ventilation, reducing internal heat and identifying higher-risk homes.

    official guidance · Accessed 2026-08-21