Heat Stroke: Causes & First Aid Treatment

Picture of Preventing Heat Stroke


Heat stroke Definition

Heat stroke is a condition caused by your body overheating, usually as a result of prolonged exposure to or physical exertion in high temperatures. This most serious form of heat injury, heat stroke can occur if your body temperature rises to 104 F (40 C) or higher.

Heat stroke requires emergency treatment. Untreated heat stroke can quickly damage your brain, heart, kidneys and muscles. The damage worsens the longer treatment is delayed, increasing your risk of serious complications or death.

Heat Stroke First Aid

If you suspect that someone has a heat stroke, immediately call 911 or transport the person to a hospital. Any delay seeking medical help can be fatal.

While waiting for the paramedics to arrive, initiate first aid. Move the person to an air-conditioned environment  or at least a cool, shady area  and remove any unnecessary clothing.

If possible, take the person’s core body temperature and initiate first aid to cool it to 101 to 102 degrees Fahrenheit. (If no thermometers are available, don’t hesitate to initiate first aid.)

Try these cooling strategies:

  • Fan air over the patient while wetting his or her skin with water from a sponge or garden hose.
  • Apply ice packs to the patient’s armpits, groin, neck, and back. Because these areas are rich with blood vessels close to the skin, cooling them may reduce body temperature.
  • Immerse the patient in a shower or tub of cool water, or an ice bath.

If emergency response is delayed, call the hospital emergency room for additional instructions.

Heat Stroke in Kids

While the elderly are at greatest risk for heat stroke, infants and children are also at risk. In particular, infants or young children who are unattended in locked a car may suffer heat-related illness quickly, since the indoor temperature of a locked car can rise to dangerous levels even in moderate weather. Rarely, infants have died of heat stroke when overly bundled in their cribs. It is critically important that parents understand the medical dangers inherent in leaving children unattended in cars in addition to the obvious safety risks. Further, cars should always be kept locked when not in use so that children may not enter them and become trapped.

Among older children and teens, heat stroke or heat-related illness is a risk for athletes who train in hot environmental conditions. Among reported heat-related illnesses in U.S. high school athletes, the majority of cases occur in football players during the month of August.

Heat Stroke Causes

The major cause of heat stroke is prolonged exposure to high temperatures and/or doing strenuous activity in hot weather. The body’s ability to control the core temperature (sweating, evaporative cooling, for example) is overwhelmed by heat.

Infants, children, pregnant females and the elderly are at higher risk for heat stroke because they are less able to control their core temperature.

Other causes that can contribute to the condition of heat stroke are:

  • Dehydration
  • Drinking alcohol
  • Dide effects of certain medications (for example, dehydration, increased urination, sweating)
  • Wearing excess and/or tight clothing can contribute to causing heat stroke by inhibiting cooling by evaporation.
  • Sunburn

Another cause of heat stroke that often results in death is leaving a child or pet in a vehicle that is not well ventilated or cooled. The average number of child fatalities due to heat stroke from being left in a car has averaged 37 deaths per year since 1998.

  • About 53% of the children were “forgotten” and left in a vehicle by an adult,
  • about 17% were intentionally left inside by an adult, and
  • the remainder were mainly children that shut themselves in an unattended vehicle.

Symptoms of Heat Stroke

The hallmark symptom of heat stroke is a core body temperature above 105 degrees Fahrenheit. But fainting may be the first sign.

Other symptoms may include:

  • Throbbing headache
  • Dizziness and light-headedness
  • Lack of sweating despite the heat
  • Red, hot, and dry skin
  • Muscle weakness or cramps
  • Nausea and vomiting
  • Rapid heartbeat, which may be either strong or weak
  • Rapid, shallow breathing
  • Behavioral changes such as confusion, disorientation, or staggering
  • Seizures
  • Unconsciousness

Risk Factors for Heat Stroke

Heat stroke is most likely to affect older people who live in flats or homes lacking good airflow and with inadequately shaded south-facing windows. Other high-risk groups include babies and young children, and people of any age who don’t drink enough water, have chronic diseases, have mental disabilities or who drink excessive amounts of alcohol. People who spend a lot of time being physically active in hot weather are also at greater risk.

The risk of heat-related illness dramatically increases when the heat index climbs to 26°C or more. So it’s important – especially during heatwaves to pay attention to the maximum temperature reported in your local weather forecasts and to remember that it will be hotter in the sun than in the shade.

If you live in an urban area, you may be especially prone to develop heat stroke during a prolonged heatwave, particularly if there are stagnant atmospheric conditions and poor air quality. In what is known as the “heat island effect,” asphalt and concrete store heat during the day and only gradually release it at night, resulting in higher night-time temperatures.

Heat Stroke Treatment

Immediate treatment of heat stroke is body cooling; currently the preferred method of cooling is evaporation cooling by spraying the patient with cold water or covering them with cold water soaked sheets, and using fans to augment evaporative cooling. Others recommend additional cooling by placing ice packs on the head, neck, armpits, and groin.

In addition, benzodiazepines can be administered to prevent shivering. Often the patient is dehydrated so IV fluids are given. The goal is to reach a core temperature (rectal probe reading with a constant readout) of below 102.2 F or 39 C. The ideal time frame for reaching this temperature is controversial but this should in general be achieved in the fastest possible time frame, ideally over the first 60 minutes. In addition, other supportive measures for breathing, hypotension, and seizures may be required.