The data show that the human body may be cooling

recently, a controversial study showed that the normal body temperature of Americans has dropped by a few degrees since the 19th century. The study analyzed more than 677,000 temperature measurements in the United States since 1860.
team led by Julie Parsonnet, an infectious disease epidemiologist at Stanford University in the United States, estimates that the average body temperature of modern people is lower than the textbook 37 degrees Celsius and drops by a few degrees every 10 years. She suspects that the decline in chronic infection rates is the cause of the body's coolness.
1851, German physician Carl Reinhold August Wunderlich first determined that the body's normal body temperature should be 37 degrees Celsius.
1992, a team at the University of Maryland tested 148 people who participated in the vaccine trial and found that their average body temperature was 36.8 degrees Celsius. In 2017, a study of 35,000 people in the UK found an average body temperature of 36.6 degrees Celsius.
, the lead author of the 1992 study and an infectious disease physician, suspects that it was the Wunderlich-era thermometers that caused the difference. Later, he tested a Wunderlich-era thermometer in his collection at the Matt Museum in Philadelphia, Pennsylvania, and found that its readings were too high, even above 1 degree Celsius. Mackowiak therefore concluded that measurement errors were behind Wunderlich's average body temperature of 37 degrees Celsius.
researchers found that people born earlier tend to have higher body temperatures than those born later, even when they are measured at the same time.
Parsonnet said this shows that advances in thermometer technology are not lagging behind this trend. "If only the thermometer had changed, the year in which the temperature was measured should have a different effect."
believe that lower infection rates may be the best explanation for hypothermia. Parsonnet points out that an inflammatory immune response to long-term infections such as tuberculosis and gum disease raises body temperature.
, However, Mackowiak does not believe that body temperature is dropping because too many variables are not taken into account. He added: "I don't think there is a convincing biological explanation. The time span of our study is 200 years, which is only a blink of an eye in the evolution of life. "
, Parsonnet thinks that human physiology has changed in other ways, so it's not surprising that people are a little cooler." We've gained weight and we've gained weight. We've been changing since the 1850s, and body temperature is just a sign of that change. (Source: Tang Erdu, China Science Daily)
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