Stanford study reveals: Normal human body temperature may be cooler than we thought

The research led by Julie Parsonnet's team at Stanford University in California indicates a slight but consistent decrease in the average body temperature of a healthy human. This conclusion is based on the analysis of hundreds of thousands of temperature measurements taken over the past 150 years.

Although a new standard has yet to be precisely established, researchers concur that the average body temperature is seemingly on a downward trend. Julie Parsonnet states that the widely known figure of 36.6 degrees Celsius (97.88 degrees Fahrenheit) we've commonly accepted as normal is inaccurate.

This claim is substantiated by studies considering around 677,000 temperature measurements taken in various time periods. These measurements include those from veterans of the Civil War, individuals from the 70s, and patients of Stanford Health Care during the period of 2007-2017.

The findings based on these data sets indicate a clear downward trend in average body temperature, dropping roughly 0.03 degrees Celsius (0.054 degrees Fahrenheit) every decade. A potential explanation for this could be the outdated standard, ranging globally between 36.6 to 37 degrees Celsius (97.88 to 98.6 degrees Fahrenheit), established by German doctor Carl Reinhold August Wunderlich in the mid-19th century.

The health status of the average person during that era might vary greatly from today due to prevalent inflammatory diseases, possibly inflating the average body temperature in historical records.

Researchers additionally pinpoint multiple other factors influencing these temperature measurements. These include the location of measurement (mouth, armpit, rectum), time of day, gender (women's temperature fluctuating slightly more due to menstrual cycles), metabolisms, recent dietary consumption, and even the time elapsed since the last meal. The precision of the measuring instruments used can also play a substantial role.

Given these variables, the researchers have abstained from defining a new standard for human body temperature, instead merely stating it appears to be lower than previously thought. As Julie Parsonnet points out, the physiology of modern individuals differs considerably from that of our ancestors.