The average human temperature has dropped by about a degree in the last 150 years.

In 1851 German doctor Carl Reinhold August Wunderlich (what a name) calculated that the average armpit temperature of 25,000 patients was 98.6F (37C). Scientists at Stamford university of studied thousands of historic medical reports including medical records of civil war soldiers and confirmed that the average temperature one hundred and fifty years ago was indeed 98.6F (37C).

They compared this to the current average human temperature and realised that the average temperature has dropped by a degree fahrenheit compared 97.5 degrees F (36.3C).

No-one knows exactly why this is the case but scientists speculate that it could be due to the fact that people back then were fighting more diseases such as tuberculosis, syphilis or gum disease so their natural defence system was working harder and their metabolism was higher. It could also be due to the fact that people are leading more sedentary lifestyles.

Who knows how cold we’ll be in a few hundred years?

https://www.newscientist.com/article/2229715-humans-are-cooling-down-so-average-body-temperature-is-no-longer-37c/

https://www.scientificamerican.com/article/are-human-body-temperatures-cooling-down/