This article comes from WeChat public account: New medical perspective (ID: HealthHorizon) , author: new medical point of view, from the title figure: Figure worm 37 ° C, which is the temperature value we have been familiar with since childhood, and is an important indicator to help us determine whether we are sick. However, according to a new study published by Stanford University, this standard may no longer apply in the future. Due to environmental changes, the temperature of modern people may have dropped from 200 years ago. Screenshot source: eLife How did 37 ° C come from? In 1851, a German doctor named Carl Reinhold August Wunderlich took a temperature measurement of all the people he might find, whether or not he was healthy. At the time, he used to measureThe body temperature instrument is 22 cm long, which was a very cutting-edge technology at the time. After taking millions of temperature measurements on approximately 2,500 subjects in Leipzig, Germany, Dr. Wunderlich calculated for the first time 37 ° C (98.6 ° F) this average normal value. Since this pioneering work, body temperature has been a key vital sign used clinically to judge health. With the development of medical science, people gradually know that the temperature of the human body is not “constant”, but fluctuates throughout the day. In addition, with changes in age, physical activity, diet and other factors, our body temperature will also fluctuate. Moreover, the body temperature measured by different body parts is also different. However, for convenience, 37 ° C is generally regarded as the “normal” average body temperature. However, many studies have questioned this “standard value” and believe that the actual average body temperature should be slightly lower. For example, later studies have found that the average body temperature is 36.8 ° C. In 2017, an analysis of nearly 250,000 body temperature measurements of more than 35,000 Britons found that the average oral temperature was 36.6 ° C. So, compared with the 19th century, is the difference between the research and estimation of “standard body temperature” due to the increasingly accurate measurement equipment and the more scientific measurement methods, or is there really a change in humans? That’s the question that Professor Julie Parsonnet’s team at Stanford University School of Medicine tried to answer in this study. Picture source: 123RF Analysis of body temperature trend across 3 historical periods Prof. Parsonnet and her team analyze three different historiesHuman temperature data set for the period, including: Medical records of US Civil War veterans (1862 ~ 1930); U.S. National Health and Nutrition Examination Survey (1971-1975); Environmental Research Group, Stanford University Comprehensive Research Database (2007-2017). Based on nearly 680,000 body temperature measurements in these data sets, researchers have developed a predictive model of body temperature over time. Overall, these data confirm what we already know about body temperature trends, such as young people, women, or people who have higher body temperature in the evening. Importantly, researchers have observed that men born in the 21st century have an average body temperature that is 1.06 ° F lower than men born in the early 19th century. Similarly, women born in the 21st century had an average body temperature lower than women born in the late 19th century by 0.58 ° F. This is equivalent to a decrease in body temperature of 0.05 ° F every 10 years. (0.028 ° C) . In 200 years, the body temperature of the three data sets has decreased over time, whether white (left) or black (right), male (blue line) Still female (red line) At the same time, in order to exclude the influence of measurement equipment and methods, the researchers analyzed the trend of body temperature changes within a single data set. As a result, they did observe similar trends in the veterans data set. Researchers believe that this continuous decline in body temperature is difficult to be measured by thermometer equipment orThe speed of method development is explained. Professor Parsonnet said: “Physiologically, we are different from the past.” So what are the reasons for this change? Potential causes of decreased body temperature Researchers speculate that the drop in body temperature is the result of changes in our environment over the past 200 years, and the changes in the environment have promoted physiological changes: our metabolic rate, or energy consumption, has decreased compared to before. In Dr. Wunderlich’s time, humans had a life expectancy of only about 40 years, untreated chronic infections (eg tuberculosis, syphilis and periodontitis) < / span> plagues most of the population. In the past 200 years, due to the improvement of medical standards, improved sanitary conditions, food availability and living standards, people’s overall nutrition and health have been greatly improved. This means that inflammation is generally reduced. Professor Parsonnet explained, “Inflammation produces a variety of proteins and cytokines that promote metabolism and increase body temperature.” In addition, the researchers also speculated that comfortable living at a constant ambient temperature could also help reduce metabolic rates. In the 19th century, the heating of houses was unstable and there was no cooling and air conditioning. Today, comfortable indoor temperatures are commonplace. Image source: Unsplash Prof. Parsonnet said: “The environment we live in has changed, including the temperature in our homes, the microbes we come in contact with, the food we get. All of these things mean that we are still experiencing subtle changes in evolution Change. “ References [1] Myroslava Protsiv, et al., (2020). Decreasing human body temperature in the United States since the industrial revolution, eLife, DOI: 10.7554 / eLife.49555 < / span> [2] Study: Human body temperature has decreased in the US since the 19th century. Retrieved Jan 13, 2020, from https://medicalxpress.com/news/2020- 01-human-body-temperature-decreased-19th.html [3] Has the Average Human Body Temperature Always Been the Same ?. Retrieved Jan 13, 2020, from https://www.livescience.com/why-has-average -human-temperature-changed.html [4] Human Bodies Have Steadily Grown Colder Over The Past Century, Evidence Shows. Retrieved Jan 13, 2020, from https://www.sciencealert.com/human-bodies -have-steadily-grown-colder-over-the-past-century [5] What Is Normal Body Temperature ?. Retrieved Jan 13, 2020, from https://www.webmd.com/first-aid/normal-body-temperature Note: This article is intended to introduce the progress of medical and health research and is not a recommended treatment plan. For guidance on treatment options, visit a regular hospital. This article comes from WeChat public account: New medical perspective (ID: HealthHorizon) , author: Medical new perspective