What is heat stroke? Why is it deadly? Which populations are at high risk for heat stroke? How can outdoor workers prevent heat stroke? This reporter interviewed Lu Zhaoqing, attending physician of the emergency department of Beijing Friendship Hospital.
Heat stroke is no small matter
Reporter: In hot weather, people often hang on to "hot people die". Recently I found out that this is really not a joke. What hazards does high temperature bring to the human body?
Lu Zhaoqing: The mechanism of maintaining a relatively stable body temperature in the human body mainly depends on the dynamic balance of heat production and heat dissipation, when the room temperature is greater than 32 degrees Celsius, the humidity is greater than 60%, the high temperature and high humidity of the external environment will make the additional heat generated by the body can not be transmitted outward, this dynamic balance is broken, resulting in heat accumulation in the body, which may cause heat stroke.
Thermal damage factors act on the body and can cause a series of pathophysiological changes, manifested by a continuous process of mild and severe, including threatened heat stroke, mild heat stroke and severe heat stroke, collectively referred to as heat-induced diseases.
Reporter: What are the manifestations of aura heat stroke, mild heat stroke and severe heat stroke?
Lu Zhaoqing: Aura heat stroke, that is, it has not yet reached the level of heat stroke, usually manifested as dizziness, nausea, fatigue, inattention, sweating, thirst, etc., body temperature is normal or slightly elevated but below 38 degrees Celsius, then if you leave the high temperature area, timely replenishment of water, salt, etc., can soon recover.
Mild heat stroke is manifested by worsening symptoms of threatened heat stroke, redness, profuse sweating, and body temperature can rise by more than 38 degrees Celsius. If it is rescued in a timely manner, it can also be recovered within a few hours.
Severe heat stroke can be divided into heat cramps, heat exhaustion and heat stroke according to different manifestations.
Heat cramps are characterized by pronounced muscle cramps with contractile pain. Spasms are most common in muscles that are constantly active, such as the muscles of the extremities and abdominals, especially the gastrocnemius muscles (one of the posterior group muscles of the lower leg). Spasms are often symmetrical, sometimes onset, sometimes relieved, the patient is conscious, and the body temperature is normal.
Heat exhaustion generally begins rapidly. Patients often have dizziness, headache, palpitations, sweating, nausea, vomiting, wet and cold skin, pale face, a brief decrease in blood pressure, followed by syncope, and an increase in core body temperature, but generally not more than 40 degrees Celsius. If treatment is not intervened in time, it will develop rapidly into heat stroke.
Heat stroke is the most severe type of heat stroke, due to exposure to high temperatures and humidity or an imbalance in the body's thermoregulation function caused by intense exercise, thermogenesis is greater than heat dissipation, resulting in a rapid increase in the core temperature of more than 40 degrees Celsius, accompanied by skin burning, impaired consciousness (e.g., delirium, convulsions, coma), and multi-organ dysfunction. Once it occurs, the mortality rate is extremely high, with a mortality rate of up to 80% in patients over 50 years of age. If you do not receive timely treatment, you will eventually die due to the failure of multiple organs such as heart, brain, liver, kidneys and muscle breakdown (rhabdomyolysis). Therefore, heat stroke is no small matter, and we must pay attention to prevention.
The key is prevention
Reporter: Which groups of people are at high risk of heat stroke?
Lu Zhaoqing: According to the cause of the disease and the different susceptible groups, heat stroke is divided into classic heat stroke (also known as non-labor type heat stroke) and labor type heat stroke.
Classic heat stroke disease is mainly due to passive exposure to the heat environment caused by the imbalance between heat production and heat dissipation of the body, and is more common in people with insufficient body temperature regulation ability (such as the elderly and infirm, pregnant women and children), accompanied by chronic underlying diseases or immunocompromised people, and those who are in a high temperature environment for a long time (such as sanitation workers, traffic police, children in closed carriages) and so on.
Labor-type heat stroke is mainly due to the imbalance between human body heat production and heat dissipation caused by high-intensity physical activity, and is mostly seen in previous healthy young people who exercise vigorously in summer, such as training commanders and fighters, firefighters, athletes, sanitation workers, construction workers, etc. Although exertional heat stroke is more likely to occur in high temperature and humidity environments, environmental conditions do not necessarily lead to the occurrence of heat stroke.
Reporter: How to prevent heat stroke? Especially outdoor workers, how should they avoid heat stroke?
Lu Zhaoqing: The key to reducing the mortality rate of heat stroke is prevention. You should avoid going out during high temperature periods, avoid direct sun, if you must go out, you need to pay attention to sun protection, you can wear sunscreen hats, umbrellas. Reasonable arrangement of outdoor activities, outdoor labor or exercise should choose the morning when the temperature is low, and pay attention to the rest in the middle, sweat a lot of salt water should drink more salt water and other supplement electrolytes and water. For the elderly and frail, chronically ill patients, children and pregnant women, it is necessary to ensure the ventilation of the living room, and appropriately open the air conditioner to cool down during high temperature periods.
Reporter: If there is a heat stroke, how should the scene be treated first aid?
Lu Zhaoqing: Heat stroke can be life-threatening, and timely treatment is the most critical. At the scene of the first aid, this should be done -
The first is to get out of the heat: immediately move the patient to a cool, ventilated place; Remove the patient's full body clothing as soon as possible to dissipate heat. Patients can be transferred to air-conditioned rooms where conditions permit, and it is recommended that the room temperature be adjusted to 16-20 degrees Celsius.
Rapid and effective cooling: Soak or spray with cold water, ice packs, cool and wet towels, etc. can be used close to the carotid arteries, armpits or groin on both sides. You can also use ice water, alcohol, etc. to wipe the skin of the whole body.
Muscles of patients with heat stroke may twitch involuntarily, do not try to feed the patient water at this time, do not put anything in the patient's mouth, to avoid airway obstruction; If the patient is vomiting, flip the patient's body so that it lies on its side to avoid aspiration.
Timely call for help, while cooling while transporting: self-help measures can not really replace medical treatment, we must let patients get professional treatment as soon as possible.
Drink water at any time
Reporter: What symptoms should be vigilant when you generally have heat stroke?
Lu Zhaoqing: After working or living in a high temperature environment for a period of time, if there is thirst, headache, dizziness, fatigue, sweating, nausea, palpitations, chest tightness, lack of concentration and other manifestations, it may be heat stroke, then you should move to a cool environment as soon as possible, drink more salty drinks or water, so as to avoid developing heat stroke.
Reporter: The three-volt day has arrived, how can ordinary people effectively prevent heat and cool down?
Lu Zhaoqing: We can start from the four aspects of food, clothing, housing and transportation.
Clothing: Loose, light-colored, breathable clothing should be worn in summer.
Food: scientific drinking water, reasonable diet. Don't wait until you're thirsty to drink water, the right way is to drink water at any time to keep the body needed.
The summer climate is hot, people's appetite is generally reduced, so it is more important to pay attention to nutritional balance and supplement enough protein, such as fish, milk, beans. Diet should be light, should not eat high-calorie, greasy, spicy food, to eat some vitamin C-rich foods in moderation, such as tomatoes, watermelon, bayberry, melon and so on.
Housing: Improve living conditions for the elderly, the chronically ill, children and pregnant women. To ensure the ventilation of the living room, the temperature of the living room is best controlled at about 26 degrees Celsius, but do not stay in the air-conditioned room for a long time, otherwise the indoor and outdoor temperature difference is too large to weaken the human body's tolerance to high temperatures.
Line: Avoid going out during high temperature periods, if you must go out, pay attention to sun protection and avoid direct sunlight.
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The "extended version" of the three volt days is coming
Three volts are the collective names of the first volt, the middle volt and the last volt, and the "volt" means that the yin qi is forced to hide underground by the yang qi.
The three-volt day of the year occurs from mid-July to mid-August in the Gregorian calendar, and its climate is characterized by high temperature, low air pressure, high humidity and small wind speed.
This year's three-volt day from July 16 -
First prostration: July 16–July 25, 10 heavens together
Nakabushi: July 26–August 14, 20 Heavens
End: August 15–24, 10 Heavens
The length of time of the "middle volt" of the three volt days is not the same, "the summer solstice three Geng several head volts", the volt is calculated from the third "Geng" day after the summer solstice, the initial volt is 10 days, the middle volt is 10 days or 20 days, and the last volt is 10 days. So there are two situations, some years of volts are 30 days, and some years of volts are 40 days.
This year's three-volt day is 40 days, which is indeed an "extended version" of three-volt days.
How hot is it on a three-volt day?
The so-called "heat in three volts", three volt days is the highest temperature of the year, humid and stuffy time. Usually the continental region is mainly hot in the head volt and the middle volt, and the southeast coastal and island areas are mostly hot at the end volt.
Meteorological data from the past 30 years (1991 to 2020) compiled by the China Weather Network shows that the extreme high temperature in the eastern part of North China, Huanghuai and Northwest China is above 40 degrees Celsius in the three-volt day, and the number of high temperature days lasts for 5 to 7 days; Although most of the south is not as strong as the north due to high humidity, it is extremely endurance, and the number of high temperature days is more than 20 days, and the local area even reaches 35 days. The "high temperature overlord" Turpan, which has to be mentioned, has an extreme high temperature of 47.8 degrees Celsius (August 5, 2008), and the number of high temperature days has lasted for 39 days.
Why is it so hot on a three-volt day?
Meteorological expert analysis ——
After the ambush, the summer wind gradually reaches the northernmost end, the surface humidity becomes larger, the heat of the surface layer accumulates, getting hotter and hotter day by day, and the accumulated heat on the ground reaches the highest peak during the three-volt day, and the weather is the hottest;
In July and August, the subtropical high pressure is strengthened, the sinking air flow inside the high pressure, under its control, the weather is clear and cloudless, which is conducive to sunlight exposure, the ground radiation warms up, and the weather is hotter;
In summer, there is a lot of rain, the air humidity is large, and the specific heat capacity of the water is much larger than that of dry air, which also affects the discharge of human sweat, which is also an important reason for the hot weather. (Wang Meihua)
Source: People's Daily Overseas Edition