Fever of 104 F (40 C) or greater.
Changes in mental status or behavior, such as confusion, agitation, slurred speech.
Hot, dry skin or heavy sweating.
Nausea and vomiting.
Flushed skin.
Rapid pulse.
Rapid breathing.
Headache. 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, aggressive behaviour or anxiety.