Heatstroke: The silent summer killer

When 62-year-old Wang was rushed to a hospital in Xiangyang City, central China's Hubei Province, his body temperature had soared to 42 degrees Celsius and his limbs were twitching. 

Local media reported on August 26 that Wang lost consciousness while working outdoors in sweltering summer heat. 

Diagnosed with severe heatstroke, he was immediately placed under rapid cooling treatment. It was not until five days later that Wang finally regained consciousness in an ICU bed.

Elsewhere in Asia, Philippine media reported last month that nearly 200 students fainted from extreme heat during a parade on July 24.

Each summer, similar stories emerge worldwide, with people collapsing – and in some cases dying – under punishing temperatures. 

In late August, a new report from the World Health Organization and the World Meteorological Organization warned that workers worldwide need better protection from extreme heat as climate change drives more frequent and intense heatwaves.

So, what happens to the body during heatstroke, and why could it be so deadly?

Not sweating might be a bad sign

Picture a construction worker laboring under the blazing summer sun, sweat pouring down his body. Soon he begins to feel short of breath and lightheaded, but continues working, thinking he will soon be fine after a short break. One hour later, he stops sweating. His body becomes eerily dry, red and extremely hot. 

That's when what many consider simple discomfort from the heat turns into a life-threatening medical emergency.

"Normally, when you're hot, you sweat, and the evaporation of that sweat cools you down. In heatstroke, this mechanism breaks down. The body can no longer cool itself and core temperature soars to dangerous levels, typically above 40 degrees Celsius. This extreme hyperthermia causes catastrophic damage to the brain, heart, kidneys and muscles. It is a true medical emergency that requires immediate treatment to prevent permanent disability or death," Chen Zhi, director of the training department of Beijing Emergency Medical Center, told CGTN.

Imagine cooking an egg white

Heatstroke isn't just "getting too hot." It triggers a catastrophic systemic inflammatory response similar to severe sepsis. The extreme core body temperature (above 40 degrees Celsius) directly damages cells and causes proteins to denature. This immense stress can lead to multiple organ failures and irreversible brain damage. 

It's also a true time-sensitive emergency as heat exhaustion could evolve into heatstroke in a few hours, and more importantly, people often underestimate its risk and mistake it for just heat exhaustion, thereby delay action until it's too late.

"The most important thing for us as emergency medical providers is to lower the core body temperature to below 39 degrees Celsius within 30 to 60 minutes of collapse, because the longer the core temperature remains critically high, the more severe the cellular damage and the higher the chance of death or permanent disability. Every minute counts," Chen said.

The story of a food delivery worker

People who work outdoors for long hours, including construction workers, food and package delivery workers, and street cleaners, are often considered at a higher risk of heatstroke.

In July, a food delivery worker collapsed from his motorbike after working long hours under the heat and passed away in Xinyang City of central China's Hunan Province.

On a sweltering summer afternoon, when the temperature was about 33 degrees Celsius, in downtown Beijing, Li Dalong, heard a "ding" on his phone. He told CGTN reporter he had received an order from someone living in a residential building about 2 kilometers away. 

Thinking that it is "not too far," he took the order. But the moment he clicked on his phone, the clock started ticking, and a 15-minute countdown began.

"Need to go now." Li walked into a shopping mall, took the escalator to B2 to find the restaurant. But the complex structure of the mall overwhelmed him. So, he had to stop to ask someone for directions. Before taking his package away after arriving at the restaurant, he checked on his phone the order number to make sure it was a match. Then he took the escalator again, walked outside the building, and put the package in the box on the back of his motorbike. He then got on the vehicle and started zigzagging in the busy commercial district. 

"10 minutes," the timer showed the time remaining. 

"It was nerve-wracking when I started, but now I can handle it," Li answered when asked whether he was nervous because of the countdown. "The most important thing is to deliver food to the customers on time."

After making three turns and riding with buses, private cars and people also on motorbikes, he got off, took the package and walked towards a building. The receptionist told him his destination was another building nearby. So more walking was needed. 

Eventually, he finished the order within 15 minutes. But before he was able to catch a breath, his phone rang again.

Li makes over 40 such trips in about 10 hours every day.

"Everyone does what they do for money, as much as possible."

Li shared with CGTN a video clip showing his delivery company giving out drinking water and medicines to each worker to help them cope with the heat.

In addition, the company pays an extra 1 yuan ($0.14) on each order when the temperature reaches 35 degrees Celsius. 

Despite these measures, the experienced deliveryman told CGTN that the job is not for the fainthearted.

Staying indoors doesn't mean it's safe

In Li's case, working long hours outdoors under constant stress contributes to the risk of heatstroke, but people staying indoors could be susceptible too. 

Local media in east China's Zhejiang Province reported on August 26 that a 73-year-old man surnamed Yang was discovered unconscious and convulsing on the floor at home and rushed to a nearby hospital. Reports say that Yang ended in ICU because he, concerned about the electricity bills, was reluctant to use his air conditioner despite the sweltering heat.

In fact, people over 65 are at a significantly higher risk of heatstroke due to a combination of physiological changes, chronic health conditions and social factors.

In addition, while temperature tells how hot the air is, humidity is the key factor that determines how effectively our bodies can cool themselves. It's not the heat alone, but the combination of heat and humidity that becomes dangerous.

Prevention is key

For most people, the best strategy is to avoid heatstroke altogether. One is advised to stay hydrated and time activities to avoid strenuous work or exercise during the hotter parts of the day. Besides, one should never leave somebody in a parked car, especially children, as the interior temperature can rise nearly 11 degrees Celsius in just 10 minutes, creating a deadly oven.

CNN reported last month that at least three young children died in the span of a week after being left in hot cars in the United States.

First aid: Act fast!

"If you suspect someone is having heatstroke, call for an ambulance immediately. Then, take these critical steps while waiting for help: move the person to a cool place, for example, the shade or an air-conditioned room; use whatever methods are available to cool the body, for example, spraying the body with cool water or applying ice packs or cold, wet towels to the neck, armpits and groin, where blood vessels are close to the skin," Chen from Beijing Emergency Medical Center told CGTN.

Against common sense

One might think drinking cold water is the solution to stay hydrated and to cool the body at the same time. In fact, drinking a lot of cold water hastily is not advised because of the severe complications it could have for a heatstroke victim, including triggering shock or vomiting. 

When one drinks a large amount of cold water, the body reacts by constricting blood vessels in the stomach and surrounding areas to maintain the core body temperature. However, forcing peripheral blood vessels to constrict suddenly sends blood back to the core, placing even more demand on a heart that is already struggling.

Since a heatstroke victim's body temperature is extremely high, many people might resort to anti-fever medicines to cool them down. However, that is not wise either because it is ineffective and can be harmful.

Fever is usually caused by the body's immune response. The brain's hypothalamus resets the body's thermostat to a higher temperature to fight an infection. Anti-fever drugs work by blocking the chemicals that cause this reset, telling the hypothalamus to lower the thermostat. On the other hand, heatstroke is caused by overwhelming external heat, and when the body's cooling mechanisms have failed. The hypothalamus is not reset; it's desperately trying to lower the temperature but is losing the battle. The thermostat is set correctly, but the "air conditioning" is broken.

Therefore, using anti-fever medicine for heatstroke is like trying to fix a car's broken engine by adjusting the GPS. It targets the wrong system, doesn't solve the problem, and wastes critical time. The only effective treatment is to cool the body down from the outside, and this is a race against time that requires immediate medical attention.

(Cover image via CFP)