Learn about heat stroke

chinacdc.cn | Updated: 2022-07-20
What is heat stroke?
According to the Expert consensus on the diagnosis and treatment of heat stroke in China, published in the online edition of the Medical Journal of Chinese People's Liberation Army, heat stroke is a life-threatening disease that occurs when the body can no longer cool itself. It is the imbalance between heat production and heat dissipation caused by exposure to heat or strenuous exercise.
Heat stroke usually occurs in summer when temperatures and humidity are both very high.
When the temperature is too high, the balance of water and electrolysis in the human body will be commpromised, causing dizziness, chest discomfort and a series of other physical discomforts, this condition is called heat illness. Heat stroke is the most serious phase of heat illness. 
Symptoms of mild heat illness include nausea, dizziness and fatigue. When these symptoms appear, one should be cautious and stay where it is cool.
Severe heat illness is defined in three stages: heat cramps occur when someone experiences physical convulsions and confusion as a result of the loss of electrolytes through excessive sweating; heat exhaustion occurs in continuous heat exposure, which can lead to the dysfunction of multiple organs; heat stroke is the most serious of all heat-related illnesses, when the temperature of the internal organs exceeds 42℃, resulting in cellular dysfunction.
Heat stroke is the disorder of body thermoregulation caused by high temperatures and excessive accumulation of heat in the body, which leads to  damages to the nerve organs.
Common symptoms of heat stroke include high fever, body temperature above 40℃, minimal or no sweating despite the heat, unconsciousness and organ failure. If not treated quickly, the fatality rate of heat stroke can range from 20 percent to 70 percent, with the fatality rate for people over 50 reaching 80 percent. 
Key groups of people who should protect themselves against heat stroke
There are two main groups of people who need to protect themselves against heat stroke
1. Healthy young people who do strenuous exercise in summer, such as soldiers participating in summer training, sportsmen, firefighters and building workers. Heat stroke normally occurs as a result of the imbalance between heat production and heat dissipation due to their high-intensity physical activities. 
2. Infants and children, pregnant women, as well as the elderly, weak, or people with chronic diseases or an impaired immune system. Heat stroke usually occurs when these people are exposed to high temperatures that cause an imbalance between heat production and heat dissipation. 
Heat stroke is not necessarily caused by exposure to the sun
Many people think that heat stroke is only related to high temperatures, but that is not always the case. 
The body's perception of heat not only depends on temperatures, but also on humidity. 
Under the same temperature and humidity, the better the ventilation, the more tolerant the human body will be to higher temperatures. Personal constitution, direct sunlight and working environments can have an impact on human heat emission and the body's regulatory functions. 
It is not just manual workers who are exposed to the sun for long periods that will suffer from heat stroke. Old and infirm city-dwellers who stay in a hot and humid environment for a long time may also suffer from this condition.
How to prevent and treat heat stroke
Prevention is very important!
The elderly, children and outdoor workers are at a higher risk of suffering from heat stroke. Please do the following to prevent heat stroke:
Avoid going out during heat
To avoid developing heat stroke or other heat-related illnesses, limit your outdoor time on hot days, especially at midday when the temperature is the highest, also avoid exposure to direct sunlight for long periods. If it can't be avoided, pay more attention to the changes in your body, and take anti-heat medicine with you when necessary.
Maintain proper ventilation and an appropriate room temperature
During periods of high temperature, air conditioners can be turned on to adjust the room temperature, 26℃ will be appropriate. Keep the room ventilated as much as possible. Do not stay in air-conditioned rooms for long hours, otherwise the excessive indoor and outdoor temperature difference will greatly reduce the human body’s tolerance and resistance to higher temperatures. 
Take protective measures for long periods of direct exposure to the sun
In hot summers, heat stroke prevention measures should be taken for outdoor activities, such as shade from direct sunlight, drinking plenty of salty water, resting and keeping a healthy daily routine, as well as avoiding working for a long time in an enclosed and hot environment. 
Timely treatment
In high temperature and humidity, if a person has symptoms of heat illness, such as a fast heartbeat, dizziness, headache and shallow breathing, please transfer the person to a cool and ventilated place to rest as soon as possible.
Once the following symptoms appear, the heat stroke may be life-threatening:
Throbbing headache
High body temperature (oral temperature above 39.5℃)
Hot, red, dry skin
Minimal or no sweating
Cold intolerance
Rapid and strong pulse
Garbled speech
Then the following measures can be taken:
Cool down body temperature
Transfer the patient to a cool place and  apply a cold compress to head, armpit and groin area with a cool and wet towel or ice bag; use cold water to wipe the patient's body or put the patient in cold water if conditions permit.
Monitor the patient's body temperature
Try to cool down the patient's temperature to 38℃
Call for help
Call 120 or 110 for assistance immediately
Do not give the patient water!
Sometimes, the patient's muscles will involuntarily cramp due to heat stroke. When this happens, please stop the patient from hurting himself/herself. Do not put anything in the patient's mouth. Do not try to hydrate them with fluids. If the patient vomits, please make the patient lie on their side to ensure the airway is unblocked. 
NB. The above self-help measures cannot replace medical treatment. Please make sure the patient receives medical treatment as soon as possible.