The average body temperature was believed to be 37°C, but it has actually dropped to 36.6°C thanks to advances in medicine and improved living conditions
There average body temperaturelong considered a fixed value of 37°Cit may no longer be the universal reference we thought. Research from Stanford University led by Julie Parsonnet has highlighted that the average temperature has gradually decreaseddropping to approx 36.6°C in the last two centuries. This change has been detected comparing historical and contemporary data collected from over 680,000 measurements.
The study analyzed three main datasets: the first, dating back to 1862, included data from veterans of the American Civil War; the second came from research carried out between 1971 and 1975; the third concerned surveys carried out between 2007 and 2017. The results showed a average drop of 0.03°C per decadea consistent trend among men and women.
According to Parsonnet, this decrease is not attributable to measurement errors, as the methods used were adequately normalized. The proposed explanation concerns i advances in medicine and improved living conditions: Vaccines, antibiotics and better access to care have reduced infections and chronic inflammation. This decreased the activity of the immune system, contributing to body cooling.
The temperature can vary between 36.1°C and 37.2°C
Body temperature is not a single, static value, but can vary within a range between 36.1°C and 37.2°C in healthy individualsdepending on factors such as age, gender, time of day and measurement site (axillary, oral or rectal).
However, the value of 37°C, established in 1868 by the German doctor Carl Reinhold August Wunderlich, may have been overestimated due to less precise instruments than modern ones. These findings have not only academic, but also clinical implications: they could influence how we define fever or hypothermia. For example, a mild fever today is considered above 37.2°C, while a full fever occurs above 38°C, often accompanied by symptoms such as chills or muscle aches.
In practice, therefore, the human body is becoming progressively “colder”, probably as reflection of a healthier humanity and less exposed to chronic immunological stress. Although the trend may stabilize in the future, further research is needed to fully understand its causes and global implications.
