The standard body temperature is dropping

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Since German physician Carl Wunderlich established 98.6 degrees Fahrenheit as the standard "normal" body temperature, parents and doctors have used it for nearly two centuries as a measure of fever, often also used to measure the severity of the disease.
, however, over time and in recent years, hypothermia in healthy adults has been widely reported. In 2017, a study of 35,000 adults in the UK found that their average body temperature was lower (97.9 degrees Fahrenheit). A 2019 study found that the normal body temperature in the United States is about 97.5 degrees Fahrenheit.
recently, a multi-country research team led by Michael Gurven, a professor in the Department of Anthropology at the University of California, Santa Barbara, found a similar drop in body temperature in the Tismans, indigenous peoples of the Bolivian Amazon. The researchers observed a sharp drop in Tisman's average body temperature over the past 16 years -- 0.09 degrees Fahrenheit a year -- and now Tisman's body temperature is about 97.7 degrees Fahrenheit.
less than 20 years, we have seen this decline at a level similar to that observed in the United States for nearly two centuries. Gurven said. Their analysis was based on a large sample of 18,000 observations from nearly 5,500 adults and was adjusted for a variety of other factors that might affect body temperature, such as ambient temperature and weight.
study shows that normal body temperature in the United States has dropped in a single population since the Civil War of the 1860s, but there is no explanation for this decline. "Obviously, some aspects of human physiology may have changed. One of the main assumptions is that over time, we experience fewer infections as a result of improved sanitation, clean water, vaccinations and medical treatment. "Although some infections
high body temperature, this does not explain the sharp drop in body temperature over time, " Gurven said. We used the same type of thermometer in most studies, so this is not due to instrument changes. Gurven points out.
study co-author Thomas Kraft, a postdoctoral student in the school's department of anthropology, added: "No matter how we analyze it, body temperature is dropping. Even if we limit our analysis to fully healthy adults diagnosed by doctors as less than 10%, we still observe that their body temperature decreases over time. A
is why the body temperature of both Americans and Thetismans has dropped over time. The large amount of data provided by the group's long-term study in Bolivia illustrates a number of possibilities. "This decline may be due to the rise of modern health care, with a lower rate of minor infections." "However, despite the overall improvement in people's health over the past two decades, infections are still widespread in rural Bolivia, and reducing infections alone does not explain the observed hypothermia," Gerven explained. This
, which he believes may be because people are in better health and therefore do less to fight infection. Or more antibiotics and other treatments mean the infection lasts longer than in the past. Consistent with this argument, Gurve said, "We found that people who developed respiratory infections at the beginning of the study had higher body temperatures than those who had recently had the same respiratory infections." But
found that even though their analysis included biomarkers of inflammation, a temporary drop in body temperature persisted.
" another possibility is that because of air conditioning in summer and heating in winter, our bodies don't have to work so hard to regulate the internal temperature. Kraft said, "Although the temperature of the Tismans does vary with the seasons and weather patterns, they do not use any advanced technology to help regulate their body temperature." However, they do have more access to clothes and blankets. There
no way to explain hypothermia. This may be a combination of factors, all of which indicate an improvement in the situation. "The Bolivian region inhabited by the Tismans is rural and tropical, with little public health infrastructure." "Our study is the first to show that body temperature has declined even in tropical environments, where infections remain the main cause of morbidity and mortality," Gurven said. "
as an important signal, temperature is an indicator of physiological changes in the body, just like a thermostat of metabolism." We already know that there is no universal 'normal' body temperature that applies to everyone at any time, so I suspect this finding will affect how clinicians use body temperature readings in practice. Gurven said. Although temperatures have been set at 98.6 degrees Fahrenheit, most clinicians believe that "normal" temperatures have a range. Through the day, temperatures can change as much as 1 degree Fahrenheit, from the lowest temperature in the morning to the highest temperature in the evening. It also changes with menstrual cycles and physical activity, and tends to decline with age.
by linking improvements in epidemiological and socioethic conditions to changes in body temperature, the study suggests that body temperature information may provide clues to people's overall health, just like other common indicators such as life expectancy. "Body temperature is easy to measure, so it can be easily added to a routine, large-scale survey that monitors the health of the population." Gurven said. (Source: Feng Lifei, China Science Journal)
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