Human body average temperature shows decline from 19th-century standards

Research indicates that the average human body temperature has decreased from the 37 degrees Celsius standard established in the 19th century to approximately 36.4 degrees Celsius today.

The historical benchmark was set by German physician Carl Wunderlich, who conducted an extensive study in the 1860s involving over one million measurements from 25,000 patients. While this figure became a universal diagnostic tool, modern data suggests a downward trend.

A Stanford University study analyzing data from nearly 190,000 people in the US between 1862 and 2017 found that average temperatures have dropped by about 0.03 degrees Celsius per decade. Similar trends were observed in the Tsimane community in the Amazon rainforest, where temperatures fell from roughly 37 degrees Celsius in the early 2000s to 36.5 degrees Celsius by 2018.

Scientists suggest several factors for this shift, including improved public health, reduced chronic inflammation, and better hygiene. Lower rates of infectious diseases like tuberculosis and dysentery mean the immune system spends less energy producing heat. Additionally, modern climate-controlled environments and lifestyle changes may contribute to the decline.