Overview

Signs of rapidly progressing heatstroke include:

• Unconsciousness for longer than a few seconds.
• Convulsion (seizure).
• Signs of moderate to severe difficulty breathing.
• A rectal temperature over 40 °C (104 °F) after exposure to a hot environment.
• Confusion, severe restlessness, or anxiety.
• Fast heart rate.
• Sweating that may be heavy or may have stopped.
• Skin that may be red, hot, and dry, even in the armpits.
• Severe vomiting and diarrhea.

After calling 911 or other emergency services, begin emergency first aid treatment if emergency medical personnel (such as paramedics) are not going to arrive soon.