What Are the Symptoms of Heat-Related Illnesses?

Heat cramp symptoms can include:

  • Severe, sometimes disabling, cramps that typically begin suddenly in the hands, calves, or feet
  • Hard, tense muscles

Heat exhaustion symptoms can include:

  • Fatigue
  • Nausea
  • Headache
  • Excessive thirst
  • Muscle aches and cramps
  • Weakness
  • Confusion or anxiety
  • Drenching sweats, often accompanied by cold, clammy skin or a sensation of prickly skin
  • Slowed or weakened heartbeat
  • Dizziness
  • Fainting
  • Agitation

Heat exhaustion requires immediate attention.

Heat stroke symptoms can include:

  • Nausea and vomiting
  • Headache
  • Dizziness or vertigo
  • Fatigue
  • Hot, flushed, dry skin
  • Rapid heart rate
  • Dry skin
  • Profound sweating
  • Shortness of breath
  • Decreased urination
  • Blood in urine or stool
  • Increased body temperature (104 degrees to 106 degrees F)
  • Confusion, delirium, or loss of consciousness
  • Convulsions

Heat stroke can occur suddenly, without any symptoms of heat exhaustion. If a person is experiencing any symptoms of heat exhaustion or heat stroke, GET MEDICAL CARE IMMEDIATELY. Any delay could be fatal. Seek emergency medical care for anyone who has been in the heat and who has the following symptoms:

  • Confusion, anxiety, or loss of consciousness
  • Very rapid or dramatically slowed heartbeat
  • Rapid rise in body temperature that reaches 104 degrees to 106 degrees F
  • Either drenching sweats accompanied by cold, clammy skin (which may indicate heat exhaustion) or a marked decrease in sweating accompanied by hot, flushed, dry skin (which may indicate heat stroke)
  • Convulsions
  • Any other heat-related symptom that is not alleviated by moving to a shady or air-conditioned area and administering fluids and salts

While heat stroke and heat exhaustion are related conditions, heat stroke is significantly more dangerous and can be fatal if not immediately and comprehensively treated. Symptoms shared by both conditions include nausea, fatigue, confusion, dizziness and fainting.

One of the most effective ways to tell the difference between the two conditions is through the sweat of the affected individual. Individuals suffering from heat exhaustion typically experience drenching sweats accompanied by clammy, cold skin, while individuals suffering from heat stroke sweat less than usual and typically have skin that is flushed, hot and dry to the touch.

Another important determining factor is the heartbeat of the affected individual. A rapid heart rate is a symptom of heat stroke, while individuals suffering from heat exhaustion typically exhibit weakened or slowed heartbeats. Both conditions require immediate medical attention, especially if the condition of the affected individual does not improve when placed in a cool area and administered salts and fluids.