What is the normal human body temperature
The human body constantly metabolizes heat, exercise generates heat, and dissipates heat to the environment. The two coordinate to maintain a constant body temperature. But warm-blooded animals, including humans, have the ability to regulate temperature through the brain body temperature center, which is located in the hypothalamic area of the human brain.
Therefore, the average body temperature of a person is not determined by cell metabolism, muscle movement, etc., but is “designed” by nature in advance.
Is the human body temperature 37℃? To be precise, 37°C is the average temperature in the oral cavity of a healthy adult at about 12 noon at room temperature and resting. This theory was first proposed by the 19th century German physicist Karl Windrich.
In 1992, the British National Medical Service System re-stated the body temperature of 148 people and found that the average body temperature of a normal person was about 36.8℃, and it fluctuated freely between 36.1℃ and 37.2℃.
In addition, many studies have also found that individual differences, age differences, different parts of the trunk, different times of the day, and some disease reactions such as inflammation will fine-tune individual temperature.
Suppose that the normal human body temperature rises by one degree
For the earth, because the energy provided by the sun has not changed, and all the energy flowing in the biosphere comes from the fixed solar energy of the producers, this part of the energy flowing through the ecosystem is eventually dissipated in the form of heat and returns to the environment.
Even if the human body temperature rises, the food intake of the individual may increase (but the total solar energy fixed by the plant remains unchanged), and the heat dissipated into the environment also increases. Therefore, the total energy should not change for the earth.
For nature, the species “human” belongs to the top of the food chain. The increase in body temperature means that the enzymatic reaction in the cell becomes more intense, so it seems that the basal metabolism will indeed increase. This means that humans need to ask for more food, and of course it also generates more heat.
The result of more human metabolic activities is global warming! However, how warm is it?
Seth Winns, a researcher at Lund University in Sweden, published an article in the journal Environmental Research Bulletin on July 12, 2017, stating that one less child can reduce an average of 58.6 tons of carbon dioxide emissions per year.
Based on this calculation, if the human body’s basal metabolism increases by 13%, each person’s carbon dioxide emissions will increase by 7.6 tons/year, while the global population (calculated at 7.5 billion) will increase carbon dioxide emissions by a net increase of 57 billion tons/year! The greenhouse effect brought by so much carbon dioxide cannot be underestimated.
For human society, because of the two major premises of increased basal metabolism and increased carbon emissions, humans will be forced to grow more food crops or, as Seth Winnes said, increase vegetarian intake To reduce the loss of energy in the energy transmission chain, or to maintain the basic energy supply at the cost of reducing the population by “family planning”.
Suppose that the normal human body temperature drops by ten degrees
Regarding the hypothesis of “if the average human body temperature drops by 10°C”, when exploring human adaptation to the environment, it can be understood that the ambient temperature has risen by 10°C. According to the human body’s tolerance to ambient temperature under normal circumstances, we can imagine a situation where the ambient temperature rises by 10°C. Is this environmental temperature no longer suitable for human survival?
To sum up, if the average human body temperature drops by 10°C, as the global “relative warming” intensifies, some areas with “heat to death” (such as Shanghai with a high temperature of 40°C) will indeed no longer be suitable for human living.
In contrast, the body temperature of cats is much higher than that of normal humans, about 38-39.5°C. Therefore, it is conservatively estimated that the cats will increase their invasion and further occupy the earth.
Of course, the above questions are purely mind-blowing, because the human body’s temperature is the result of interaction with the environment, and it is impossible to suddenly increase or decrease. In the regulation of human body temperature, what effect will the change of human body temperature have on ourselves? In fact, the change of basal metabolism is only one aspect, and some serious related scientific research has confirmed that the truth is far more exciting than we thought.
Can increased body temperature reduce the fungus that infects humans?
This is one of the few scientific insights around the topic of “why we need to maintain a body temperature of 36.8°C”. Some scientists believe that relatively high body temperature can discourage most fungi from our bodies.
Professor Arturo Casadvor’s research confirmed that between 27°C and 40°C, for every 1°C increase in temperature, 6% of fungi lose their ability to infect the host. This is why there are tens of thousands of species of fungi that can infect reptiles and amphibians and other temperature-changing animals, but only a few hundred species can threaten humans and other mammals.
However, the obvious disadvantage of raising body temperature is that humans need to get more calories from food to maintain body temperature.
The author also proposed that increased body temperature will also bring other benefits, such as maintaining physical mobility, allowing mammals to escape from the claws of large predators. After the extinction of the dinosaurs, the high body temperature capable of resisting fungal infections made mammals the dominant creatures on earth.
However, there are still many controversies surrounding this theory. First of all, the impact of fungal infections on humans is actually unknown. It is true that some fungi are pathogenic, but most fungi are harmless to the human body, so whether mammals are really just to resist fungi at the expense of raising body temperature remains to be further verified.
In addition, if more food is needed to maintain body temperature, warm-blooded animals have to increase their foraging activities, thereby prolonging their exposure to predation risk. Therefore, the consideration of the living environment is an indispensable part of the benefits and disadvantages of raising the body temperature of animals.
Lower body temperature and prolong life?
More recent research reports have shown that hypothermia can prolong life.
In 2006, American scholar Bruno Conte published this article in the top academic journal “Science”. They specifically expressed a protein called uncoupling protein 2 in nerve cells near the hypothalamus preoptic region of the mouse body temperature regulation center, which can cause local temperature rise in response to the release of heat energy. The thermoregulatory center will sensitively capture this change, and mistakenly believe that the body temperature rises, which initiates the thermoregulatory response for heat dissipation.
Bruno Conti and others established a mouse model with a body temperature of 0.3-0.6℃ lower than that of normal mice through this principle, and finally found that the average life span of mice with lower body temperature was longer than normal. Male mice with low body temperature have an average life span of 89 days longer than normal male mice, while female mice have a longer life span of 112 days. It should be understood that for mice with an average life span of only 2-3 years, these 100 days are equivalent to one-tenth of the life span, and this change is only caused by a decrease in body temperature of less than 1°C.
The higher the body temperature, the faster the time passes
This experimental conclusion, like the theory of relativity, was published in the “Experimental Psychology Quarterly” as early as 1995. In the article, John Weldon and others at Keele University in the United Kingdom conducted research on the perception of time under the condition of changing body temperature from 1927 to 1993.
They asked subjects with different body temperatures to record “what they think” for 100 seconds with a stopwatch. They found that subjective time changes were negatively correlated with body temperature changes, that is, when the body temperature was higher than 37°C, the subjects The often felt time lapses faster (subjective time becomes shorter); when the body temperature is lower than 37°C, the opposite is true (subjective time becomes longer). The researchers speculated that it is likely that the high temperature caused the release of certain hormones, which made neurotransduction more exciting.