The earth is warming like a microwave oven. In it, humans are like eggs. It is predicted that by the end of this century, the planet's temperature will increase by about 3-5 ° C.
Right now, in some areas such as India and Pakistan, peak heat waves have caused mass deaths when outdoor temperatures reach 50oC. Like frogs sitting in a pot of boiling water, we are not aware of what is going on.
So how exactly will global warming affect our bodies? Why can a peak heat wave kill you?
How can climate change kill you?
How the body regulates body temperature
Like most mammals and birds, humans are endothermic (hot blood). Internal animals have the ability to maintain body temperature from the inside, less affected by temperatures outside the environment.
For example, humans always maintain their internal operating temperature to an optimal level of about 36.8 ° C +/− 0.5. If you sit quietly in a room with a temperature of 22 ° C, your body will have to produce passive heat to increase it by another 15 ° C, to keep your body temperature at about 37 ° C.
Conversely, when the ambient temperature is greater than 37 ° C, you must radiate excess heat into the environment, through mechanisms such as sweating. The rate of body's heat exchange with the environment is determined by the spectrum of heat between the skin's surface and the surrounding air layers.
When the surrounding air is hot and humid, the process of losing heat slowly, we will keep the heat and our body temperature rise. That's why a hot, dry climate is still more comfortable than a humid tropical climate: dry air is easier to absorb sweat.
In the case of wind, the wind blows to the skin with dry air to replace the heated layer and to saturate the sweat, helping to speed up heat release and make us even more comfortable.
4 COOLING MECHANISM OF THE BODY
1. Heat conduction
If you hold a cup of iced tea in the summer, the physical contact between the hand and the teacup will transfer heat from the body into it, causing your body temperature to drop. But it's insignificant, heat conduction only accounts for about 2% of the body heat that you lose or want to lower.
The convective cooling mechanism accounts for a higher proportion, about 10%. That's when you transfer heat directly into air or water, and the air is then blown away or pushed away from you, replaced by a cooler air or water stream. Turn on the fan when it is cold and take a cold shower in the shower, that is you are cooling down by the convection mechanism.
About 35% of the heat is lost from your body by evaporation. That's when your body sweats, transmitting heat to sweat, causing sweat to fly away.
Heat will radiate to transfer from hot objects to cold objects. This amount of heat can account for about 65% of heat loss throughout your body. Unfortunately in the summer, when the outdoor temperature is greater than 35oC, heat transfer under radiation mechanism becomes less efficient.
If the ambient temperature is greater than your body temperature, the opposite effect will occur. The heat from the outside will heat your body, like a chicken roasted in an oven.
What happens if the body is too hot?
Death – it is a possibility that the human body is exposed to temperatures that are too high to cool itself to maintain body temperature within safe limits. Like an egg in a microwave, the protein in our bodies is mutated when exposed to heat.
An increase in the ambient temperature leads to an increase in mortality.
When our body temperature reaches 38.5 ° C, most people will begin to feel tired. Symptoms continue to rise as the body temperature escalates, going beyond the safe working range of vital organs like the heart, brain and kidneys.
Take for example the heart, its task is like a pump that maintains blood pressure for the body. As the body temperature increases, the heart rate and the force it produces during each contraction also increase in response to the heavier workload.
The heart must pump a hot stream of blood to fill the dilated blood vessels throughout the body, to bring blood and oxygen to vital organs. If your muscles are also working, they need even higher blood flow.
If all of this happens at the same time, you will persistently sweat resulting in dehydration. As a result, blood volume also decreases while thicker blood requires more vigorous heart activity.
The heart itself is also a muscle, so it also needs extra blood supply when working hard. But when the pump is strong and fast, the blood flow to the heart will no longer meet its own needs. The result is a heart attack, as many deaths have been recorded under hot weather.
Not only in the elderly and the elderly, many young athletes also have heart failure leading to death in this condition.
Reaching 40 ° C, except for some elite athletes, such as those taking part in the Tour de France race that can tolerate it for a limited time, most ordinary people will facing the risk of death.
Reaching the 40 ° C level, most normal people will face the risk of death.
High risk subjects
As noted, older people are the first to be alert to the risk of heat stroke. Age is often associated with reduced physical activity, poor thermoregulation. Even many elderly people do not realize they are thirsty or too hot.
Obesity also increases this risk because fat acts as an insulating layer that makes the body's cooling process less effective. Obese people also put more weight on their hearts, because they have a bigger body that needs blood supply, while the muscles have to work harder to control the body.
People who are treating illnesses must use certain medications that can reduce the body's ability to withstand heat, as the drug interferes with the natural cooling mechanisms we use to cope with high temperatures. .
These include medications that lower the heart rate, lower blood pressure by dilating blood vessels or interfering with sweating.
In addition, pregnant women are also susceptible to the effects of temperature, as hormonal reactions and metabolic acceleration during pregnancy automatically make their body temperature about half a degree higher than normal.
The fetus is developing and the placenta also needs extra blood flow. If unresponsive, pregnancy during periods of high temperatures can also increase the rate of premature birth and other health problems for the fetus such as congenital heart defects.
Older people are the first to be alert to the risk of heat stroke.
Can we humans adapt to rising temperatures?
The truth is that our bodies can adapt to hot temperatures, but this process has its limits. Some heat levels are simply too hot, beyond the heart's tolerance. Before that, the sweating process no longer cools down the body, especially when we are exercising or exercising.
The human body is also limited by the functioning of the kidneys. It cannot save water and electrolyte permanently. But the amount of water intake is limited by the capacity and absorption time of the intestine.
Adapting to heat requires the body to sweat, which will lead to dehydration and electrolytes. Both of these processes affect cardiac activity.
Right at this time, extreme heat waves in India and Pakistan have caused mass deaths. That is when the outdoor temperature reaches 50 ° C, which exceeds the adaptability of the human body.
Climate change is causing heat waves to last longer and occur more often. We can't stay indoors forever with air conditioning, because we still need to go outside to travel, work, shop and take care of the weak.
Our people, our animals and our social systems are like frogs in a pot of boiling water.
On days when the outdoor temperature was up to 50 ° C, the air conditioners had to struggle to remove 25 ° C from the indoor air, pushed outside, very few people realized the situation they were in. face to face. Even if we realize, what can we do to jump out of that pot of water?