If you have always thought it was “cool” to be a human being – you are right! Especially, since researchers have found that over the last 100 years or so, our body temperatures have been dropping!
A recent analysis of temperature trends suggests that the average human body temperature has dropped since the 19th century. Most people don’t even really think about temperature unless they are not feeling well, but body temperature can be influenced by other factors such as lifestyle habits, age, and ambient temperature. Body temperature is a marker of metabolic health, and according to the authors of this recently published study, it indicates metabolic rate, which has been linked to longevity and other things such as body size.
In 1851 a survey conducted by Carl Reinhold August Wunderlich involving 25,000 people in one city, established that 37 degrees Celsius or the familiar, 98.6 degrees Fahrenheit, is the standard temperature of the human body. But recent analyses and surveys suggest the average temperature is now lower, as a study of over 35,000 people in the UK and close to 250,000 temperature measurements found that 36.6 degrees Celsius, or 97.9F, is now the average oral temperature.
So why are we cooling down? The researchers say we are simply changing with the times. “Physiologically, we’re just different from what we were in the past,” says, Dr. Julie Parsonnet, lead researcher on the project. “The environment that we’re living in has changed, including the temperature in our homes, our contact with microorganisms, and the food that we have access to. All these things mean that, although we think of human beings as if we’re monomorphic and have been the same for all of human evolution, we’re not the same. We’re actually changing physiologically.”
Parsonnet believes the average metabolic rate has declined over time, and this decrease could result from a reduction in inflammation. “Inflammation produces all sorts of proteins and cytokines that rev up your metabolism and raise your temperature,” she says. Additionally heating and air conditioning have resulted in “a more consistent ambient temperature that makes it unnecessary to expend as much energy as was once required to maintain the same body temperature”, Parsonnet added.