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Signs and Symptoms of Heat-Related Illnesses

June 22, 2021

Summer has only just started, and that means it’s time to get serious about sun safety. With longer days, higher temperatures, and stronger UV rays, it’s prime time for heat-related illnesses to strike.

Heat cramps, heat exhaustion, and heat stroke all occur when the body is exposed to high temperatures and is unable to cool itself. As the body struggles to lower its core temperature, it sends blood to the surface of the skin, leaving less for the brain and muscles, which can lead to mental confusion and muscle weakness.

Temperatures easily reach the upper nineties during Minnesota summers, so knowing how to spot the signs of and treat heat-related illnesses is the key to staying cool.

Heat Cramps

While less serious than heat exhaustion and heat stroke, heat cramps are painful, often occurring during physical activity in hot or humid weather. They can be an early symptom of worse heat-related illnesses, making them an important warning. Look for heavy sweating and involuntary muscle spasms, usually in the larger muscles being strained in the heat; for example, heat cramps might develop in the legs if you’re running or cycling.

To treat heat cramps, rest somewhere cool to lower your body temperature and gently stretch the cramping area. Replenish your fluids with water and/or an electrolyte-rich sports drink. Even after the cramps fade, it’s best not to continue the activity you were previously doing—rest for a few hours instead.

Heat Exhaustion

Heat exhaustion occurs when your body loses an extreme amount of water and salt through sweat. Without the necessary fluids to cool itself, the body is unable to properly cool itself. Symptoms of heat exhaustion include:

  • Muscle cramping and weakness
  • Fever
  • Rapid pulse
  • Pale, clammy skin
  • Nausea
  • Headache
  • Fatigue
  • Fainting

Like heat cramps, heat exhaustion should be treated by moving to a cool, shady place and rehydrating. If possible, you can use towels soaked in cold water to cool your skin or take a cooling bath to lower your temperature.

Heat Stroke

Also called sunstroke, heat stroke is the most serious form of heat-related illness and can be deadly, damaging the brain and other internal organs. Heat stroke is most common in older adults, but it can happen to any dehydrated individual exposed to prolonged high temperatures. While it often appears as a progression of the above stages, heat stroke can also develop without any signs of other heat-related illnesses.

A core body temperature of 104 is a telltale sign of heat exhaustion, as well as:

  • Dizziness or fainting
  • Lack of sweat
  • Shallow breathing
  • Flushed skin, hot and dry to the touch
  • Muscle cramping and weakness
  • Confusion
  • Headache
  • Seizure
  • Loss of consciousness

A person suffering from heat stroke may not realize it, but you should call 911 immediately if you suspect you or someone around has developed heat stroke. While waiting for help, perform the first aid you’d use to treat heat exhaustion: move to a cool, shaded area—air conditioned if possible—and replenish your lost fluids.

Lower the core body temperature by wetting the skin and fanning air to initiate cooling; applying ice packs or rags soaked in cold water to the armpits, neck, back, temples, and wrists; or taking a cold shower. Ice baths are also a viable treatment for exercise-induced heat stroke, though ice shouldn’t be used for seniors, children, and those with chronic illnesses.

Learn more about the best ways to protect yourself from heat-related illnesses on the Specialized Health and Safety blog.