It is important to know the risk of heat stroke and to deal with it seriously. Not only does heat stroke have a relatively high mortality rate, even those who recover from it can face the following problems: future health problemsSaid Orlando Raitano, Assistant Professor of Applied Physiology and Kinesiology at the University of Florida. “We now believe that heat stroke is akin to a concussion.”
of a recent studyLaitano et al. found that heatstroke in mice alters the genome and may increase susceptibility to future heatstroke and immune disorders.
About 30% of humanity is now exposed to hazardous environmental heat for at least 20 days each year. According to recent research. This number could rise to her 74% of the world’s population by 2100, if man-made climate change does not stop.
“When you’re faced with global warming and climate change, it’s a hot topic — no joke,” said Raitano, co-author of the paper. recent reviews About heat stroke.
Understanding heat stroke and heat stroke
Anyone can develop heat-related illnesses, but the elderly and young children suffer from heat stroke. particularly vulnerable. High humidity, strenuous physical activity, and hot and humid nights also increase the risk.
The severity of heat stroke varies from mild heat exhaustion to life-threatening heat stroke. heatstroke It is more common and may be accompanied by symptoms such as dizziness, fatigue, nausea and headache, but without a dramatic rise in body temperature.
Heatstroke, usually defined as a core body temperature above 104 or 105 degrees Fahrenheit, causes severe central nervous system dysfunction, including confusion, dizziness, and unconsciousness, and can lead to multiple organ damage, among other things. I have.
But heat tolerance varies greatly from person to person, and some fall below this threshold, Raitano said.
Another potential challenge is that heat stroke can skew judgment, and people with heat stroke may not be aware that they are in trouble.
How Our Brain Coordinates Thermoregulation
Our body’s cells function properly only in a relatively narrow range of temperatures. The temperature of a healthy human is regulated between 98 and 99.5 degrees Fahrenheit (36.7 and 37.5 degrees Celsius). Extreme heat damages our cells, breaking down proteins and damaging DNA.
“When you’re in that state, things stop working and you see a series of damaging effects on your body,” says Stearns.
Our central nervous system works hard to regulate body temperature to prevent harm. Temperature sensors called thermoreceptors in our skin and internal organs are specially tuned for different temperature ranges and send signals to the brain’s contact cortex. This allows us to perceive heat and respond to things like moving indoors away from the sun. .
Our brain also has an internal thermostat called the thermostat in the hypothalamus. preoptic area. By sensing our core body temperature, it activates an automatic autonomic system that initiates cooling when the body reaches a certain temperature, such as through sweating or dilation of blood vessels.
The main way we cool our bodies is by sweating through our sweat glands. When sweat evaporates, it cools our skin. This evaporative cooling accounts for about 80 percent of your cooling capacity during exercise, Stearns said.
But sweating is a “double-edged sword,” says Raitano. “This is very important as it not only helps regulate body temperature but also leads to dehydration.”
Our brain’s internal thermostat also activates the sympathetic nervous system, causing blood vessels in the skin to dilate.our hearts More than double Its output increases as demand increases, and warm blood is pumped from the core of the body to the surfaces where it should be cooled, provided the outside air temperature is not too high.
Hot and humid days are especially dangerous for heat stroke because they challenge our natural ability to regulate body temperature. Hot air raises skin temperature rather than lowers it, and the higher the humidity, the more difficult it is for sweat to evaporate and cool the body.
2 types of heatstroke
there is 2 types of heatstroke: Typical heat stroke and exertional heat stroke.
Classical heatstroke is caused by passive heating from the external environment, such as during heatwaves. It usually affects children and the elderly who have trouble regulating their body temperature. Young children may not have developed sweat glands. fully developed.And with age we begin to lose both abilities feel thirsty and regulate body temperature Effectively.
Exertional heat stroke occurs when you exercise vigorously in the hot sun. When physical activity expends energy, it heats up skeletal muscle. The more intensely the muscles contract, the more heat is generated, adding to the ambient heat to warm our body from the inside.
Exertional heat stroke can affect anyone who is physically active, but young people, such as athletes and military personnel, are particularly susceptible.
“In everyday life, you don’t see much of that outside of competitive scenarios because people are smart and if they get sick they stop before they get heatstroke,” Stearns said. .
However, those involved in sports and military affairs may push the limits of thermoregulation. Exertional heat stroke is the third leading cause of death in physically active athletes, after heart disease and head and neck injuries.
Exertional heat stroke is estimated to kill about 1 million people. 27 percentClassic heat stroke mortality, on the other hand, is likely to be much higher, as it is more prevalent in people who are already vulnerable.
Effects of heatstroke on the brain
Early data show that 10 to 28 percent of patients who survive heatstroke may endure: long-term cognitive or neurological damageIn particular, it involves dysfunction of the cerebellum, a brain region important for coordinating our movements.
Brain imaging months or years after the heat stroke also found damage to brain cells. cerebellum Other brain regions such as the hippocampus, midbrain, and thalamus can also be damaged.
“This is going to be really sad. It’s very rare that anyone survives the long-term damage from heat stroke,” Stearns said. “Unfortunately, most of those cases die. But many require lifelong care.”
Prevention and treatment of heat stroke
Give yourself time to acclimate to the heat and stay hydrated. “When doing any new activity in a warm environment, it’s very important to do it gradually for the first 10 to 15 days because it gives your body time to adapt,” says Stearns. rice field.
Do not exercise outdoors alone. signs of heatstroke in yourself and in others. Escape from the heat, even for a few hours, protection during heat waves. Air conditioners and fans are helpful, but they may not always be available, such as during a power outage. Soaking the skin in water effective alternative.
If you feel sick, weak, confused, or agitated, those are all “red flags,” says Stearns. Tripping, falling, or being unable to coordinate your movements are also signs to watch out for yourself and those around you.
If you suspect heat stroke, start cooling immediately, even before a full diagnosis is made, experts say. “There’s a big link between how quickly you cool people down and the prognosis of what the outcome will be,” Raitano said.
You can also apply ice wrapped in a towel to the neck, groin, and extremities. cold water immersionThe first-line treatment for heatstroke is to immerse the whole body in ice water.
With better education, more people’s awareness and prompt treatment, “heat stroke doesn’t have to be fatal,” says Stearns.
Have questions about human behavior or neuroscience? Email [email protected] I may answer that in a future column.
