In recent days, the Second Affiliated Hospital of Zhejiang University School of Medicine has admitted four patients with "heatstroke" in succession. "The mechanism behind heatstroke can actually be explained by the outward flow and dissipation of environmental heat," explained Wu Hongbo, attending physician at the Emergency Center of the Second Affiliated Hospital. High-temperature objects always transfer heat to lower-temperature objects. In a high-temperature environment, the body's thermoregulatory center commands the body to maintain normal temperature through sweating. "However, persistent sweating may lead to sweat gland dysfunction, and when internal body temperature accumulates to a certain level, it can damage the thermoregulatory center. Therefore, when the internal temperature reaches over 40 degrees Celsius, various organs in the body may begin to fail."
Heatstroke can be categorized under heat-related illnesses and is considered an extremely severe form of heat illness. Generally, mild heat illness symptoms include dizziness, nausea, and fatigue, while severe heat illness may lead to limb convulsions, unconsciousness, and the most dangerous cases can result in organ failure.
"Seventy percent of the patients this year developed symptoms at home, and their common characteristic is that they are elderly and frail, and their homes had no air conditioning," said Wu Hongbo. In previous years during the peak of summer, hospitals also treated patients with heatstroke, but those patients were mostly heavy laborers working under the scorching sun, classified as occupational heat illness. Wu Hongbo believes this is closely related to the unusually high temperatures this year. In the past, if the outdoor temperature was around 35–36 degrees Celsius, opening windows for ventilation and using fans could reduce the indoor temperature to around 32–33 degrees Celsius. But this year, with outdoor temperatures exceeding 40 degrees Celsius, even a drop of two or three degrees would still be roughly equal to last year’s outdoor temperatures. "Therefore, it is very necessary for the elderly to use air conditioning at home. If symptoms of heat illness appear, do not ignore them—seek hospital treatment early for a higher chance of recovery."
Aside from heat illness, there are other common emergencies during hot weather, such as hypokalemia and acute sunburn. Hypokalemia is a complication often caused by diarrhea, vomiting, and excessive sweating in the summer, leading to a drop in potassium concentration in the blood. This is followed by symptoms such as physical fatigue, weakness, and delayed reactions. In severe cases, it can cause limb convulsions, generalized muscle weakness, drowsiness, and unconsciousness.
The symptoms of hypokalemia are similar to those of heat illness, but while rehydrating can alleviate discomfort from heat illness, hypokalemia requires potassium supplementation. Doctors recommend drinking sports drinks appropriately and consuming more potassium-rich foods such as lean meat, green leafy vegetables, bananas, and soy products.
During hot weather, Hangzhou Third People's Hospital is also seeing a busy period. In recent days, the daily outpatient volume has surged from the usual 5,000+ to over 6,000, with the Dermatology Department becoming the busiest due to the increasing number of acute sunburn cases under the scorching sun. "There were almost no cases of acute sunburn in previous years, but yesterday alone I treated five cases," said Wang Ping, director of the Second Dermatology Department at the hospital. Acute sunburn is more likely to occur among people engaging in activities by the sea, but the cases he encountered were caused by rafting or swimming outdoors.
Acute sunburn can cause the skin to turn red and develop numerous blisters, along with itching and pain. "To prevent acute sunburn, try to avoid going out between 10 a.m. and 4 p.m.," said Wang Ping. When going outside, take precautions such as wearing sun-protective clothing, using umbrellas, and applying sunscreen.
Acute sunburn can cause the skin to turn red and develop numerous blisters, leading to itching and pain. "To prevent acute sunburn, try to avoid going out between 10 a.m. and 4 p.m.," said Wang Ping. When going out, it's important to take proper sun protection measures, such as preparing sun-protective clothing and umbrellas, and applying sunscreen.