Have you ever had such doubts? Obviously, the normal body temperature of healthy people is 37 ° C, but most people measure their body temperature in daily life, which is lower than 37 ° C, mainly floating between 35 ° C and 36.7 ° C. Why is this?
In fact, stanford University School of Medicine in the United States has long found that compared with the past (since the 19th century), the average body temperature of adults has been declining, from 37 ° C to 36.6 ° C. So why does our body temperature keep getting lower?
Why do most people have a body temperature below 37°C?
Do you know how normal body temperature comes from? This was concluded by a German doctor named Carl Wunderlich who measured the underarm temperature of 25,000 people by using a 12-inch (about 30cm) long thermometer and taking a underarm measurement.
In modern research, most of the current measurement of sublingual temperature is the mainstay, and it is found that only 8% of them have a normal body temperature (sublingual) at 37 °C, and the overall average body temperature is 36.8 °C. It can be said that 37 °C has become history.
In addition to the drop in body temperature, in fact, the body temperature of the human body is not always fixed, it has been fluctuating.
In general, the normal body temperature is 36.5 ° C - 37.2 ° C, more than 37.3 ° C is a fever.
However, the selected measurement sites are different, and the measured values are also different, such as the normal value of the oral and tongue temperature is 36.3 °C-37.2 °C, the rectum is 36.5 °C-37.7 °C, the underarm temperature is 36 °C -37 °C, and the ear temperature is 35.7 °C -37.5 °C.
In addition, body temperature can be affected by various factors such as day and night, age, gender, activity, drugs, etc., such as the rest state, before eating, the body temperature will be lower; and after exercise, after eating, the body temperature will be slightly higher. However, the range is very small, generally not more than 0.5 °C ~ 1.0 °C.
So, in general, as long as the body temperature does not exceed the standard range too much, everyone does not need to worry too much.
Second, the higher the body temperature, the stronger the immunity?
There are many theories about body temperature. Scientists have said that for every 1 degree Celsius drop in body temperature, immunity will be reduced by 30%. In addition, Professor Wang Xiaochuan of Tongji Medical College of Huazhong University of Science and Technology also said that within the normal body temperature range, the higher the body temperature, the stronger the immunity.
A study recently published in the journal PNAS also showed that moderate body temperature increase will well enhance the metabolic process and anti-tumor function of CD8+ effector T cells and enhance the body's immunity.
The latest study recently published in "Nature Metabolism" by the Chinese Academy of Sciences gave a different answer, which found that compared with metabolic rate, body temperature has a greater impact on life expectancy, and maintaining a lower body temperature is conducive to prolonging life.
The study took haddock hamsters as experimental subjects and divided them into 2 groups, one group was raised at 32.5 °C (group A) and one group was raised at 21 °C (group B).
The results showed that the average body temperature of the hamsters in group A was 0.5 °C higher, the average metabolic rate was 40% lower, and the lifespan was shorter, and the average lifespan of female hamsters was reduced by 28.2%, and the male rats were reduced by 40.9%. However, if ventilation can be maintained at high temperatures, it can also play a role in reducing body temperature and prolonging life.
That is to say, people are best to stay in a constant temperature environment, otherwise if they continue to stay in a high temperature environment, they may really die of "heat". Of course, whether the body temperature drops or rises, as long as it is maintained at the right level, it is good.
Third, how high is a person's body temperature and will die?
It is not impossible to be "heated" to death, the existing human body temperature limit is 46.67 ° C, if this temperature is exceeded, it will really be life-threatening.
The core body temperature of the normal human body is maintained at about 37 ° C, according to the degree of fever, it can be divided into low fever (37.3 ° C ~ 38 ° C), moderate fever (38.1 ° C ~ 39 ° C), high fever (39.1 ° C ~ 41 ° C), ultra-high fever (above 41 ° C).
In the process of continuously rising body temperature, the body will also have some changes, as follows:
1, burn to 37.5 °C
At this time, the hypothalamus thermoregulation center can sense the signal of "body heat", and in order to dissipate heat, it will make the body's heat dissipation system "work overtime".
At this time, the skin will secrete a lot of sweat, resulting in water loss, so people will feel very thirsty, plus the blood flowing to the brain at this time has become less, so many people will feel headaches, dizziness, and inability to concentrate.
2, burn to 38 °C
In order to continue to dissipate heat, capillaries further expand, resulting in redness of the human face, hot skin, and because of the decline in the activity of various enzymes in the body, people will become weak and tired, and some people will feel hot and cold.
3, burn to 40 °C
At this time, the skin is like a fire, the heat is amazing, in order to better dissipate heat, the blood of the whole body will be more arranged to the bones, skin, so that the visceral blood flow will become less, including heart function, brain, and then lead to people's consciousness began to blur.
At this time, you may make some behaviors that are very different from usual, such as not being able to control your emotions, being easy to get angry, and some hallucinating.
4: Burn to 42 °C
At this time, the heart, liver, kidneys and other organs will be damaged, the cells of the whole body will be irreversibly damaged and exhausted, the various organ systems of the body will also be "abandoned", and the human body will face life threats.
Therefore, usually everyone should pay attention to controlling body temperature. Recently, temperatures have continued to rise, and some people who are engaged in heavy physical strength or work in hot environments.
Especially those who are malnourished, old and weak, suffering from chronic diseases, etc., should pay attention to the prevention of heat stroke, headache, dizziness, palpitations, increased body temperature, nausea, vomiting, spasms and other symptoms in time to cool down.
Whether the body temperature is decreasing or rising, as long as it is maintained at the right level, it is good. If the body temperature is too high, it is necessary to cool down in time, drink more water, rest more, and reasonably cool down physically (such as using anti-fever stickers or cold towels).
If the situation is more serious, it is best to go to the hospital as soon as possible to find out the cause, and use antipyretic drugs or anti-inflammatory drugs as directed by the doctor to avoid "burning" the body.
Resources:
[1] If people's body temperature continues to rise, how many degrees will they burn to death? 》. Tencent Medical Code.2022-05-04
[2] "No longer 37°C, human body temperature generally drops, how many degrees of body temperature is considered healthy?" 》. Health Times. 2022-03-24
[3] Seriously, does a fever burn out the brain? You should really look at the fever as a bad thing". Popular Science China .2019-01-17
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