Medical Term Definition

Heat Exhaustion

Heat exhaustion is a heat-related illness that occurs when the body loses excessive water and salt through sweating and cannot adequately cope with heat exposure.

It may develop after prolonged exposure to high temperatures, strenuous physical activity in hot conditions, or working in environments where heat and humidity make it difficult for the body to cool itself. Heavy sweating, dehydration, and inadequate replacement of fluids and salts can contribute to the condition.

Common symptoms include heavy sweating, weakness, dizziness, headache, nausea, muscle cramps, thirst, and a rapid pulse. The person may feel faint or unusually tired. Unlike heatstroke, heat exhaustion does not typically involve the severe central nervous system dysfunction that characterizes a medical emergency caused by extreme overheating.

A person with suspected heat exhaustion should stop physical activity, move to a cooler or shaded place, loosen unnecessary clothing, and begin cooling the body. If the person is fully alert and able to swallow safely, small, frequent sips of cool water or an appropriate oral rehydration drink may help.

Heat exhaustion can progress to heatstroke. Seek urgent medical help if symptoms worsen, do not improve promptly with cooling, or include confusion, seizures, collapse, or reduced consciousness. Do not give fluids by mouth to someone who is confused, unconscious, or unable to swallow safely.

QUICK FACT

Heat exhaustion and heatstroke are not interchangeable terms. Heatstroke is more dangerous and requires immediate emergency treatment.

COMMONLY CONFUSED WITH

  • Heatstroke: A life-threatening heat-related emergency involving severe overheating and central nervous system dysfunction.
  • Dehydration: A condition in which the body loses more fluid than it takes in. Dehydration can contribute to heat exhaustion but can also occur independently.
  • Heat cramps: Painful muscle cramps associated with exertion in hot conditions, often involving fluid and electrolyte losses.

SEE ALSO