What is the difference between heat exhaustion and heat stroke

In heat stroke, the body temperature reaches 104 degrees or higher.  Heatstroke may develop following heat exhaustion if the condition is not treated.

Heat exhaustion is usually accompanied by a fever no higher than 104 degrees Fahrenheit, excessive thirst, nausea, fainting, cool and clammy skin, weakness, muscle aches, heavy sweating, slow heartbeat and dizziness. Heatstroke may develop following heat exhaustion if the condition is not treated.