What is Heat Stroke?
Heat stroke happens when the body’s core temperature elevates to dangerous levels and the central nervous system can’t work efficiently. It is a serious medical condition that requires immediate emergency care.
Heat stroke is a common condition in countries with hotter climates. However, as a result of global warming, it is happening more often in temperate regions as well. Predictions from scientific sources indicate heat waves are likely to occur more often. (1)
Recognizing and treating heat stroke quickly decreases the chance of permanent damage to the body, or at worst death.
Symptoms
While heat stroke can happen to anyone, some people are more predisposed to this condition.
Classic heat stroke happens due to an increase in temperature and humidity and its onset is usually gradual.
Exertional heat stroke occurs as a result of vigorous exercise which increases the body’s core temperature and can happen suddenly. The onset is quick and can occur when the weather is more temperate, even as low as 21 degrees Celsius. (2)
Older people are more vulnerable to classic heat stroke, in fact the highest death rates due to heat exposure occur in individuals over 60 years of age. (3)
Young children are also more at risk of developing classic heat related conditions. (4)
Other risk factors are obesity, cardiovascular disease, diabetes mellitus and respiratory disease. These conditions render the body less able to deal with, and adapt to environmental conditions, leading to heat related illnesses. (5)
People performing physical work, like laborers, or people who exercise vigorously in higher temperatures are at risk of exertional heat stroke. (6)
The symptoms of heat stroke manifest when the body is unable to regulate its core temperature and include:
Temperature
The recognized core temperature for onset of heat stroke is 40 degrees celsius or 104 degrees fahrenheit. The preferred method of monitoring temperature in cases of heatstroke is with a rectal thermometer.
This is the main symptom of this condition. (7, 8)
Changes in Mental State or Behavior
Impaired function of the brain and central nervous system are a classic symptom of this condition. Manifesting as confusion, delirium, slurred speech or irritability, marked changes in behavior or mental state will be seen.
A person might appear to be confused, irrational and disorientated, not knowing where they are or what is happening. On occasion they may even become aggressive.
Someone who has heat stroke can experience seizures and unconsciousness, this can even lead to coma. Headaches might also be present.
This symptom differentiates heat stroke from other forms of heat related illnesses. (9)
Change in Sweating
A person who has classic heat stroke brought on by a temperature change in hot weather will no longer sweat. The skin will feel hot and dry when touched.
However, when heat stroke is the result of strenuous exercise, the skin may feel dry or damp. It will not be sweaty but may have a slight amount of moisture.
The lack of sweat indicates the body is no longer able to cool itself. This symptom also differentiates heat stroke from other heat illnesses. (10)
Skin
We have mentioned how the skin will feel, hot and dry and possibly slightly moist. It can also appear red and flushed. (11)
Breathing
Breathing rate will be fast and shallow. People might experience a shortness of breath and their lips could display a blue hue. (12)
Heart Rate
When a person has heat stroke their heart rate will be abnormally quick. The pulse will be very fast, over 130 beats per minute and strong. The heart beat can also be irregular, speeding up and then slowing down. (13)
Muscle Soreness
Exertional heat stroke can result in muscle pain and weakness. This symptom called rhabdomyolysis happens when the muscles begin to break down and release damaged cells into the bloodstream.
Some of these cells are a protein called myoglobin, which can harm the kidneys and might lead to kidney failure. Indications of this are aching muscles, muscle cramps and dark colored urine. (14, 15)
Nausea and Sickness
Vomiting, nausea and sickness might accompany other symptoms of heat stroke.
Stages
While there are no stages of heat stroke there are stages of heat related conditions. The body will generally overheat gradually so we will examine the different types of heat related conditions.
Heat illnesses, if not treated at an early stage, tend to get progressively worse, leading from one stage to the next. Therefore, it’s important to recognize the symptoms of each stage.
Heat Cramps
Heat cramps are intermittent muscle spasms which might be associated with sodium loss and dehydration. This temporary condition usually happens when people sweat excessively while doing physical exercise or working in high temperatures.
They can also happen if you spend too much time in the sun and don’t hydrate properly.
Cramps or spasms will be felt in the muscles, generally in the legs, arms or abdomen, and can be painful.
Moving somewhere cool and drinking water combined with rehydration salts will normally resolve this condition. (16, 17)
Heat Stress
This happens when the body is no longer able to cool itself by sweating. The fluid and salts lost from the body might not be adequately replaced.
Sweating is the body’s natural way of cooling, moisture evaporates from the skin to achieve this. If temperatures are high, humid evaporation might not happen. The body is unable to rid itself of excess heat and core temperature rises. (18)
Heat Exhaustion
The next stage in unrecognized and untreated heat illnesses is heat exhaustion. The body still sweats but cannot cool itself sufficiently and the volume of blood circulating in the body decreases.
Water and salts are lost, core temperature rises, however, the central nervous system is not damaged.
Symptoms include excessive sweating, weakness, fatigue, headache, dizziness, nausea and vomiting, muscle cramps, fainting and vertigo. Skin will feel cold, clammy and be pale in color. Breathing will be rapid, and the pulse fast and weak.
Heat exhaustion can be relieved by moving to a cool place and sipping water or rehydration drinks. Reduce temperature in a cool bath or by placing cool wet towels or clothes on the body.
If symptoms persist for more than an hour, worsen or vomiting is present, seek immediate medical help. (19, 20)
Heat Stroke
The final and most serious heat related illness is heat stroke, presenting with the symptoms we have already described.
The differences to note between heat exhaustion and heat stroke are: a core temperature of 104 degrees or higher, lack of sweating and presence of changes in mental state and behaviour. Other differences are flushing, redness, dryness and heat in the skin.
Treatment
Heat stroke is a serious medical condition which requires immediate emergency treatment. Call an ambulance straight away and move the affected person to a cool place. While waiting try and cool the person with cold wet clothes or in a cool bath. Do not give any drinks.
If a person is unconscious place them on their side and monitor their vital signs. Be prepared to give CPR should they stop breathing. (21)
Treatments administered by medical professionals will aim to lower the core body temperature and limit damage to internal organs.
Cooling methods include:
Conductive Cooling
Immersing a patient in cold water or an ice bath will help cool the body. Other methods include applying cold packs or placing ice slush over all or part of the body, or using cooling blankets.
Vigorous massage is likely to be undertaken to counter the constriction of blood vessels due to the cooling process.
Evaporative or Convective Cooling
This involves the use of fans to cool an undressed person in a room kept at between 20 to 22 degrees celsius.
Another method is to spray an undressed person with lukewarm water whilst continuously fanning at the same time.
If available, a specialized bed that sprays cold water over the whole body might be used. This keeps the wet skin at a constant temperature of 30 to 32 degrees to chill the body. (22)
During cooling treatments medication might be administered to stop shivering, which can be counterproductive and increase temperature. (23)
Intravenous fluids to counteract losses of salts and potassium may also be administered. Any life threatening events will be monitored and treated accordingly. (24)
FAQ
What is heat stroke? Heat stroke happens when the body’s core temperature elevates to dangerous levels and the central nervous system can’t work efficiently.
What are the signs of heat stroke? Signs of heat stroke include: a high body temperature of 104 degrees fahrenheit or higher and hot, red, dry, or damp skin. Headaches, confusion, anxiety, irritability, dizziness,loss of consciousness, rapid shallow breathing and a fast strong pulse are further symptoms.
How do you develop heat stroke? During a heatwave older people and younger children are more vulnerable to heat stroke. Also people with medical conditions including obesity, cardiovascular disease, diabetes mellitus and respiratory disease are at risk. They are unable to adjust to prolonged high temperatures and become dehydrated and the core body temperature rises to dangerous levels. Exertion heat stroke can affect anyone who works in, or exercises vigorously in, high temperatures.
How are you diagnosed for heat stroke? Diagnosis of heatstroke revolves around symptoms. Reading body temperature rectally is common, accompanied by observance of mental and behavioral changes (confusion, loss of consciousness) which might indicate heat stroke. Further blood and imaging tests might be done to detect any resulting damage to the body.
What is the best treatment for heat stroke? Cooling the body to reduce core temperature is the primary concern when treating heat stroke.
What are the long term complications of heat stroke? Heat stroke can cause damage to internal organs including the kidneys, liver and brain. Immediate treatment is imperative to prevent these conditions developing.
Is heat stroke considered a disability? Heat stroke itself is not considered a disability, however, related damage could qualify for disability purposes.
Is there a cure for heat stroke? Cooling the core temperature of the body alleviates the symptoms of heat stroke.
Is heat stroke life threatening? Yes, this condition is potentially life threatening and can affect vital organs and cause damage if untreated.
Summary
Heat stroke happens when the body’s core temperature elevates to dangerous levels and the central nervous system can’t work efficiently. It is a serious medical condition that requires immediate emergency care.
It’s important to recognise heat related illnesses to prevent them progressing to heat stroke. This can decrease the chance of permanent damage to the body, or at worst death.