"Military and Military Sub-Planes" Author: Strapdown Chu Guidance
Under the impact of the recent epidemic, Junwu Bacteria has also fully experienced the power of the Beijing strain.
▲Yesterday a fan friend guessed that military bacteria are still sprinting to the finals
First there was a high fever, and then there were the seven tortures of circulated on the Internet: cutting the throat with a knife, sealing the nostrils with cement, opening the head without anesthesia, drilling the eyeballs with an electric drill, cutting the waist with a guillotine, swallowing a sword in the throat, and sitting on a durian on the buttocks.
But what puzzles me the most is that when I first have a fever, I feel quite uncomfortable, but my body temperature is only 37.8℃. I clearly remember that it was always said that a person's normal body temperature is 37 degrees. Why is it so uncomfortable when the fever is so high? Is the thermometer wrong?
Later, after looking through the information for a long time, I discovered that the body is still honest. The reason why the body temperature is just 37.8℃ is because the standard body temperature of modern people is indeed lower than before.
In most people's minds, the most standard body temperature is between 36.8℃ and 37℃. But in fact, according to research in recent years, this standard may have really changed.
Human body temperature is indeed declining
Human body temperature refers to the temperature inside the human body, such as the temperature of the abdominal cavity, chest cavity, rectum, mouth, brain, etc., rather than the temperature of the surface skin. Eskimos can endure the cold of the Arctic, while Africans have long been accustomed to the heat day after day. This is because the human body has a central temperature regulation system.
From a certain perspective, body temperature has become one of the important reference indicators of physical health, and standard body temperature has been determined by people nearly two hundred years ago.
In 1851, a German physician named Karl Wunderlich collected the armpit body temperature data of 25,000 patients. After sorting the data, he found that the normal body temperature of the human body is approximately 37°C, so 37°C was determined for the first time as the normal body temperature of humans.
Over the next nearly 200 years, 37°C as the standard body temperature has gradually become the most widely known common sense in our lives. Therefore, there is an obvious mark (usually red) on the thermometer 37°C, which is intended to remind us that exceeding 37°C means there is something wrong with your body.
If calculated according to this standard body temperature, experts generally believe that if an adult's body temperature reaches 37.7°C, he or she is sick and has a fever.
The reason why the human body maintains its body temperature at around 37°C is actually the result of natural evolution. Previously, scientists have conducted experiments to simulate a human body with a body temperature between 30°C and 40°C, and calculate how to replenish energy to maintain the body's operation.
Experimental results show that when the human body is around 37°C, it can use the smallest power to maintain the balance of body needs. In other words, 37°C is the result of optimization of human body temperature during the natural evolution process.
In the past, we have always believed that the human body temperature should remain within the range of 36-37°C without changing. However, when people usually enter and leave public places, the measured body temperature is 35°C-36°C. People who don't know it think the thermometer is broken.
This is enough to show that the standard body temperature does not apply to everyone. In recent years, more and more studies and data surveys have shown that human body temperature is indeed gradually declining.
As early as December 2017, Harvard Brigham and Women's Hospital published a paper in the journal BMJ. The paper pointed out that researchers conducted approximately 243,506 temperature checks on 35,488 adults in the UK.
The results showed that the average oral temperature of these subjects was only 36.6 degrees, and they were all healthy people. It can be seen that the average body temperature has dropped.
In January 2019, Julie Parsonnet, a professor of medicine at Stanford University in the United States, published a research report in "elife". Their survey data volume was larger than that of the UK, and the time span was also very long.
They used data from a total of more than 500,000 people, including: Union veterans of the Civil War (23,710 people; measurement year 1 860–1940), National Health and Nutrition Examination Survey I (15,301 persons; 1971–1975), and Stanford University Translational Research Omnibus (150,280 persons; 2007–2017).
The results were found through comparative analysis that in less than two hundred years since the 19th century, the average body temperature of Americans has shown a continuous downward trend:
The average body temperature of men born in the 21st century is 0.0% lower than that of men born in the early 19th century. 59℃;
The average body temperature of women born in the 21st century is 0.32℃ lower than that of women born in the 1890s (the historical data for women is not that old)
In other words, the average body temperature of humans will drop by 0.03℃ every 10 years. According to the latest data, the average body temperature of Americans is already below 37°C, dropping directly to 36.6°C.
In October 2020, the Science sub-journal "Science Advance" published a research result by researchers from the University of California, Santa Barbara.
This paper, titled "Rapidly declining body temperature in a tropical human population," researched and recorded the body temperatures of primitive tribesmen living in the Bolivian Amazon in South America.
This primitive tribe named Tsimane has been isolated from the world for many years. It is said that the body temperature value of humans in areas where there is basically no urban pollution and greenhouse effect is of most reference significance. However, surveys have found that the general body temperature of tribal residents has dropped from 37℃ to 36.5℃ in more than ten years.
Researchers combined this body temperature detection result with many previous studies and concluded that the body temperature of all humans should be on a downward trend.
Various signs indicate that the drop in human body temperature should be an indisputable fact. So why has the human body temperature dropped since it was already said that 37°C is the optimal solution?
Why does human body temperature drop?
Some people say that the weather is getting hotter and hotter, while people are getting colder and colder. As for the reasons for the drop in human body temperature, scientists around the world have put forward many conjectures. One of the "evolutionary theories" is that "human beings lower their own body temperature to adapt to the environment."
With human activities, a large amount of greenhouse gases are emitted into the atmosphere, causing the earth's temperature to rise. Compared with more than a hundred years ago, the current average temperature of the earth has increased by about 0.5°C.
Some scientists believe that because global temperatures are rising, if humans' own body temperature remains at 37°C, it will destroy the DNA replication of biological enzymes and affect metabolism . Therefore, it is necessary to lower the body temperature to adapt to the gradually rising global temperature.
At the same time, the increase in external temperature may help the human body save some energy consumption. The human body no longer needs so much energy to maintain body temperature. basal metabolism will decrease accordingly, and the body temperature will of course also decrease.
Of course, this is just speculation and has not been verified. In addition to this "evolutionary theory", there is also a theory that it is due to changes in human living environment. It is said that in the past one or two hundred years, with the development of industry, the living environment of human society has greatly improved, which is likely to affect body temperature.
In the past, when the weather was cold and people did not have enough to eat or wear warm clothes, the central body temperature regulation system would be very "hard-working". But now, people can use air conditioners, heaters, and electric blankets to increase the ambient temperature, and eat high-calorie foods to replenish the energy they need.
When the weather is hot, air conditioners are still everywhere, which makes the body temperature regulation center no longer sensitive to the external environment temperature, becomes "lazy", and the body's heating ability also decreases.
In order to prove the impact of modern lifestyle on human body temperature, scientists found aboriginal people who had not been exposed to modern lifestyle and found that their average body temperature was generally higher than that of modern people. At the same time, scientists have also discovered that after being infected with diseases such as inflammation, aboriginal people will consume more energy and speed up their metabolism, leading to an increase in body temperature.
In contrast, we eat, drink and poop in a clean environment, with fewer opportunities to be exposed to microorganisms and bad weather, and the opportunities for immune military training in the body are also greatly reduced. Even if you are infected and sick, there are antibiotics and anti-inflammatory drugs, and the chance of fever is drastically reduced, so the normal human body temperature generally shows a downward trend.
At the same time, compared with ancient times, people today are less likely to contract malaria, tuberculosis and other diseases from food. Even if we are unfortunately infected with relevant pathogens, we will be cured quickly through drug treatment and reduce the chance of fever
Human beings' 37°C was originally intended to use higher temperatures to resist the infection of deadly fungi and viruses in the body. Now in such a clean environment, there are fewer opportunities to be exposed to microorganisms and bad weather, and the opportunities for immune military training in the body are also greatly reduced, so the body temperature naturally decreases.
However, there is a bug in this statement, that is, although the body's immune system is poorly trained, there is no evidence that the temperature that the current pathogen can tolerate has been reduced. Therefore, the most likely possibility is that the industrialization process has led to changes in microorganisms in the human body, thus causing a decrease in body temperature.
In the 1990s, people have discovered that if the microorganisms in animals are removed, the body temperature of the animals will drop. For example, studies have found that the body temperature of germ-free animals is generally about 2°C lower than when bacteria are present; if antibiotics are used to kill the intestinal microorganisms of animals such as rabbits, mice, and pigs, their body temperatures will drop by 1-2°C.
Professor Rosenberg. Eugene of Tel Aviv University in Israel published an article in 2016, in which he discussed in detail the relationship between intestinal microorganisms and body temperature. The article
stated that microorganisms, like all cells, generate heat as long as they are alive, and they convert heat more efficiently than animals. Generally, the faster the microorganism grows, the lower the rate of heat generated per unit weight, and vice versa.
For example, intestinal bacteria have an estimated average heat production of 168mW/g, equivalent to 0.0403cal/sec per g bacteria, and the resident bacteria of the human colon weigh approximately 300g dry weight (NIH Human Microbiome Project 2012 estimate), which would produce approximately 12cal/sec or 43kcal/h.
Assuming that heat is distributed on a person weighing 70 kilograms and there is no heat loss, then in a theoretical state, the theoretical energy generated by intestinal bacterial metabolism can account for about 70% of the body's internal heat, and its role can be imagined.
However, with the current abuse of antibiotics, the reduction in the proportion of natural foods, the dietary pattern with an increased proportion of processed foods, the use of infant formula, modern drugs and sanitation facilities, the composition of people's intestinal flora has been significantly changed.
You must know that using antibiotics for only a few days can severely damage the intestinal flora and kill a large number of bacteria. However, it will take weeks or even months to return to the level before treatment, and it may not be fully recovered.
People now eat almost sterile food and water. While sterilizing, they do not provide bacteria. Over time, the number of bacteria in the body that can contribute to the increase in body temperature will naturally be greatly reduced, and a drop in body temperature is inevitable.
Of course, this issue has always been controversial in the medical research community. Currently, there is no single factor that can completely explain the reason for the decrease in human body temperature. However, this also shows that the gradual decrease in human body temperature is the result of the combined effect of multiple factors.
What are the effects of a drop in body temperature?
Human body temperature has generally dropped, and the most direct question is whether the original 37.7°C fever temperature line can still be used. According to statistical data, the normal body temperature of most people has dropped to 36.5°C, and there is currently no unified statement.
Originally, doctors could understand the condition by measuring body temperature, but now more and more they can only rely on patients' self-reports. Since everyone's physique is different, they have different feelings about colds and fevers, which makes it difficult for doctors to judge the condition.
Nowadays, a popular saying about low body temperature is that people with low body temperature indicate a slow metabolism and poor health. So the body temperature of modern people is constantly dropping, will it affect health?
According to scientific research, biological enzymes and other hormones in the human body have different activities at different temperatures. The enzymatic reaction speed needs to be at the most suitable temperature to reach its maximum.
These biological enzymes are generally very sensitive to temperature. The optimal temperature for their reaction is around 37°C. If the body temperature is too high or too low, the activity of biochemical enzymes will be inhibited, thereby reducing the body's immunity.
Therefore, as a warm-blooded animal, human body temperature needs to be maintained in a relatively stable range to ensure the normal operation of immune function . Moreover, the vast majority of bacteria, viruses, fungi and other microorganisms that populate the world are also very sensitive to temperature.
A scientific research team measured the temperature at which fungi survive based on the characteristics of animals that are not infested by fungi. The measurement results found that -4℃-30℃ is the temperature at which most fungi survive. Once this range is exceeded, it is difficult for them to survive. And less than one-third of fungi can survive in an environment of 37°C.
Later, scientists combined the temperature suitable for the survival of mammals with the temperature that can protect against fungi, and found that the temperature with the least energy consumption and the best defense capability is 36.7°C, which is basically the standard human body temperature.
According to clinical studies, an increase in body temperature may stimulate the activation of more immune cells in the body, which can help eliminate invading pathogens, and fever is the product of the immune mechanism fighting various pathogens.
However, there is no definite evidence to prove that a drop in body temperature will damage immunity . Current research can only prove that the drop in body temperature is mainly related to blood flow speed and metabolic rate, but is not necessarily related to immunity.
Just like some athletes, their basal body temperature is relatively low due to regular exercise, but you cannot say that athletes have poor resistance.
Due to low body temperature, people's metabolic intensity will weaken, which can be said to be a mixed blessing. On the one hand, a slow metabolism means that you are more likely to gain weight if you eat the same amount as others, and you are less active. Reduced exercise leads to a decline in physical fitness. But on the other hand, a slow metabolism means that cells synthesize proteins at a slower rate, which is good for keeping cells young.
In 2006, American scholar Bruno Conti published a paper in Science. By comparing the life span of normal mice and mice with a body temperature 0.3-0.6 degrees Celsius lower, he found that the average life span of mice with low body temperature was longer than that of normal mice.
Among them, male mice with low body temperature lived an average of 89 days longer than normal male mice, and females lived 112 days longer. And you must know that for mice whose average life span is only 2-3 years, these 100 days are equivalent to extending their life span by one-tenth.
The reason behind this change is that the body temperature of the mice dropped by less than 1℃.Lowering the body temperature of mice can extend their lifespan. However, after all, animal experiments cannot be equated with human experiments. Therefore, when human body temperature drops, the conclusion of whether human lifespan will also be extended cannot be casually drawn.
Therefore, there is no need to deliberately wear less in winter in order to look younger or even extend life, because humans are endothermic animals after all, and their body temperature will not drop just because they wear less. The reduction of human body temperature is a long-term and slow process of adapting to the environment.
As a change in human adaptation to the environment, hypothermia is a product of modern lifestyle. We cannot fully know the pros and cons of hypothermia. As the climate environment continues to change and the epidemic era continues, human survival will face many challenges. As humans, we definitely hope that the benefits of lowering body temperature will be as great as possible, rather than posing a threat to our survival.
However, evolution itself is like opening a blind box. No one knows what color the next chocolate will be. This in itself is not a matter of someone's will.
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